Work 1 the structure of the atom. Fundamentals of the structure of the atom. Just about the complex. History of discovery and structure

laboratory works

workshops

independent classroom work

independent homework (standard calculation)

control (defenses, colloquia, test, exam)

Textbooks and study guides

N.V. Korovin. general chemistry

General chemistry course. Theory and problems (under the editorship of N.V. Korovin, B.I. Adamson)

N.V. Korovin and others. Laboratory work in chemistry

Calendar plan

electrolytes,

Chemical equivalent

hydrolysis, PR

Electric form-

13(2 )

GE, electrolysis,

27(13,16)

14(2 )

corrosion

quantum number

17(2 )

18(2 )

Chemical bond

complexes

Thermodynamics

Kinetics.

6(2,3 )

Equilibrium

Introduction to chemistry course

Chemistry at the Energy Institute is a fundamental general theoretical discipline.

Chemistry is a natural science that studies the composition, structure, properties and transformations of substances, as well as the phenomena that accompany these transformations.

	M.V. Lomonosov						D.I. Mendeleev
	“Chemical
							"Fundamentals of Chemistry" 1871
	considers		properties
							d.) – “Chemistry –
	changes
							the doctrine of the elements and
	explains
							their connections."
				chemical

transformations are taking place."

"Golden Age of Chemistry" (late XIX - early XX centuries)

Periodic law of D.I. Mendeleev (1896)

The concept of valency introduced by E. Frankland (1853)

Theory of the structure of organic compounds A.M.Butlerov (1861-1863)

Theory of complex compounds A. Werner

The law of mass action by M. Gultberg and L. Waage

Thermochemistry, developed mainly by G.I. Hess

Theory of electrolytic dissociation by S. Arrhenius

The principle of moving equilibrium by A. Le Chatelier

J.W. Gibbs phase rule

The theory of the complex structure of the atom Bohr-Sommerfeld (1913-1916)

Significance of the modern stage of development of chemistry

Understanding the laws of chemistry and their application allows you to create new processes, machines, installations and devices.

Obtaining electricity, fuel, metals, various materials, food, etc. directly related to chemical reactions. For example, electrical and mechanical energy is currently mainly obtained by converting the chemical energy of natural fuel (combustion reactions, the interaction of water and its impurities with metals, etc.). Without an understanding of these processes, it is impossible to ensure the efficient operation of power plants and internal combustion engines.

Knowledge of chemistry is necessary for:

- formation of scientific outlook,

- for the development of figurative thinking,

- creative growth of future specialists.

The modern stage in the development of chemistry is characterized by the widespread use of quantum (wave) mechanics for the interpretation and calculation of the chemical parameters of substances and systems of substances and is based on a quantum mechanical model of the structure of the atom.

An atom is a complex electromagnetic microsystem, which is the carrier of the properties of a chemical element.

STRUCTURE OF THE ATOM

Isotopes are varieties of atoms of the same chemical

elements that have the same atomic number but different atomic numbers

Mr (Cl) \u003d 35 * 0.7543 + 37 * 0.2457 \u003d 35.491

Fundamentals of quantum mechanics

Quantum mechanics- behavior of moving micro-objects (including electrons) is

the simultaneous manifestation of both the properties of particles and the properties of waves is a dual (corpuscular-wave) nature.

Energy quantization: Max Planck (1900, Germany) -

substances emit and absorb energy in discrete portions (quanta). The energy of a quantum is proportional to the frequency of radiation (oscillations) ν:

h is Planck's constant (6.626 10-34 J s); ν=с/λ , с – speed of light, λ – wavelength

Albert Einstein (1905): any radiation is a flux of energy quanta (photons) E = m v 2

Louis de Broglie (1924, France): electron is also characterizedcorpuscular-waveduality - radiation propagates like a wave and consists of small particles (photons)

		Particle - m,		mv , E=mv 2
	Wave - ,			E 2 \u003d h \u003d hv /
	Connected wavelength with mass and speed:
		E1 = E2;		h/mv
	uncertainty			Werner Heisenberg (1927,
Germany)		work	uncertainties		provisions
(coordinates)		particles x and	momentum (mv) not		may be

less than h/2

x (mv) h/2 (- error, uncertainty) I.e. the position and momentum of a particle cannot be determined in principle at any time with absolute accuracy.

Electron Cloud Atomic Orbital (AO)

That. the exact location of a particle (electron) is replaced by the concept of the statistical probability of finding it in a certain volume (near the nuclear) space.

The movement e- has a wave character and is described

2 dv is the probability density of finding e- in a certain volume near the nuclear space. This space is called atomic orbital (AO).

In 1926, Schrödinger proposed an equation that mathematically describes the state of e in an atom. Solving it

find the wave function. In a simple case, it depends on 3 coordinates

An electron carries a negative charge, its orbital represents a certain charge distribution and is called electron cloud

QUANTUM NUMBERS

Introduced to characterize the position of an electron in an atom in accordance with the Schrödinger equation

1. Principal quantum number(n)

Determines the energy of an electron - energy level

shows the size of the electron cloud (orbitals)

takes values ​​from 1 to

n (energy level number): 1 2 3 4 etc.

2. Orbital quantum number(l) :

determines - the orbital angular momentum of the electron

shows the shape of the orbital

takes values ​​- from 0 to (n -1)

Graphically, the AO is represented by the Orbital quantum number: 0 1 2 3 4

Energy sublevel: s p d f g

E increases

l=0	s-sublevel s-AO
	p-sublevel p-AO

Each n corresponds to a certain number of l values, i.e. each energy level is split into sublevels. The number of sublevels is equal to the level number.

1st energy level → 1 sublevel → 1s 2nd energy level → 2 sublevels → 2s2p 3rd energy level → 3 sublevels → 3s 3p 3d

4th energy level → 4 sublevels → 4s 4p 4d 4f etc.

3. Magnetic quantum number(ml)

defines – the value of the projection of the orbital angular momentum of the electron on an arbitrarily selected axis

shows - the spatial orientation of the AO

takes values ​​– from –l to + l

Any value of l corresponds to (2l +1) values ​​of the magnetic quantum number, i.e. (2l +1) possible locations of an electron cloud of a given type in space.

s - state - one orbital (2 0+1=1) - m l = 0, because l = 0

p - state - three orbitals (2 1+1=3)

m l : +1 0 -1, because l=1

ml =+1

m l =0

m l = -1

All orbitals belonging to the same sublevel have the same energy and are called degenerate.

Conclusion: AO is characterized by a certain set of n, l, m l , i.e. certain sizes, shape and orientation in space.

4. Spin quantum number (m s )

"spin" - "spindle"

determines - the intrinsic mechanical moment of an electron associated with its rotation around its axis

takes the values ​​- (-1/2 h/2) or (+1/2 h/2)

n=3

l = 1

m l = -1, 0, +1

m s = + 1/2

Principles and rules

Electronic configurations of atoms

(in the form of electronic configuration formulas)

Indicate the numbers of the energy level number

The letters indicate the energy sublevel (s, p, d, f);

Sublevel exponent means number

electrons at a given sublevel

19 K 1s2 2s2 2p 6 3s 2 3p 6 4s 1

minimum

Electrons in an atom occupy the lowest energy state corresponding to its most stable state.

1s 2s 2p 3s 3p 3d 4s 4p 4d 4f

Increase E

Klechkovsky

Electrons are placed sequentially in orbitals characterized by an increase in the sum of the main and orbital quantum numbers (n + l) ; for the same values ​​of this sum, the orbital with a lower value of the principal quantum number n is filled earlier

1s<2 s < 2 p = 3 s < 3 p = 4 s < 3 d = 4 p и т. д

Electrons

The concept of an atom originated in the ancient world to denote the particles of matter. In Greek, atom means "indivisible".

The Irish physicist Stoney, on the basis of experiments, came to the conclusion that electricity is carried by the smallest particles that exist in the atoms of all chemical elements. In 1891, Stoney proposed to call these particles electrons, which in Greek means "amber". A few years after the electron got its name, English physicist Joseph Thomson and French physicist Jean Perrin proved that electrons carry a negative charge. This is the smallest negative charge, which in chemistry is taken as a unit (-1). Thomson even managed to determine the speed of the electron (the speed of an electron in orbit is inversely proportional to the orbit number n. The radii of the orbits grow in proportion to the square of the orbit number. In the first orbit of the hydrogen atom (n=1; Z=1), the speed is ≈ 2.2 106 m / c, that is, about a hundred times less than the speed of light c=3 108 m/s.) and the mass of an electron (it is almost 2000 times less than the mass of a hydrogen atom).

The state of electrons in an atom

The state of an electron in an atom is a set of information about the energy of a particular electron and the space in which it is located. An electron in an atom does not have a trajectory of motion, i.e., one can only speak of the probability of finding it in the space around the nucleus.

It can be located in any part of this space surrounding the nucleus, and the totality of its various positions is considered as an electron cloud with a certain negative charge density. Figuratively, this can be imagined as follows: if it were possible to photograph the position of an electron in an atom in hundredths or millionths of a second, as in a photo finish, then the electron in such photographs would be represented as points. Overlaying countless such photographs would result in a picture of an electron cloud with the highest density where there will be most of these points.

The space around the atomic nucleus, in which the electron is most likely to be found, is called the orbital. It contains approximately 90% e-cloud, and this means that about 90% of the time the electron is in this part of space. Distinguished by shape 4 currently known types of orbitals, which are denoted by Latin letters s, p, d and f. A graphic representation of some forms of electronic orbitals is shown in the figure.

The most important characteristic of the motion of an electron in a certain orbit is the energy of its connection with the nucleus. Electrons with similar energy values ​​form a single electron layer, or energy level. Energy levels are numbered starting from the nucleus - 1, 2, 3, 4, 5, 6 and 7.

An integer n, denoting the number of the energy level, is called the main quantum number. It characterizes the energy of electrons occupying a given energy level. The electrons of the first energy level, closest to the nucleus, have the lowest energy. Compared with the electrons of the first level, the electrons of the next levels will be characterized by a large amount of energy. Consequently, the electrons of the outer level are the least strongly bound to the nucleus of the atom.

The largest number of electrons in the energy level is determined by the formula:

N = 2n2,

where N is the maximum number of electrons; n is the level number, or the main quantum number. Consequently, the first energy level closest to the nucleus can contain no more than two electrons; on the second - no more than 8; on the third - no more than 18; on the fourth - no more than 32.

Starting from the second energy level (n = 2), each of the levels is subdivided into sublevels (sublayers), which differ somewhat from each other in the binding energy with the nucleus. The number of sublevels is equal to the value of the main quantum number: the first energy level has one sublevel; the second - two; third - three; fourth - four sublevels. Sublevels, in turn, are formed by orbitals. Each valuen corresponds to the number of orbitals equal to n.

It is customary to designate sublevels in Latin letters, as well as the shape of the orbitals of which they consist: s, p, d, f.

Protons and neutrons

An atom of any chemical element is comparable to a tiny solar system. Therefore, such a model of the atom, proposed by E. Rutherford, is called planetary.

The atomic nucleus, in which the entire mass of the atom is concentrated, consists of particles of two types - protons and neutrons.

Protons have a charge equal to the charge of electrons, but opposite in sign (+1), and a mass equal to the mass of a hydrogen atom (it is accepted in chemistry as a unit). Neutrons carry no charge, they are neutral and have a mass equal to that of a proton.

Protons and neutrons are collectively called nucleons (from the Latin nucleus - nucleus). The sum of the number of protons and neutrons in an atom is called the mass number. For example, the mass number of an aluminum atom:

13 + 14 = 27

number of protons 13, number of neutrons 14, mass number 27

Since the mass of the electron, which is negligible, can be neglected, it is obvious that the entire mass of the atom is concentrated in the nucleus. Electrons represent e - .

Because the atom electrically neutral, it is also obvious that the number of protons and electrons in an atom is the same. It is equal to the serial number of the chemical element assigned to it in the Periodic system. The mass of an atom is made up of the mass of protons and neutrons. Knowing the serial number of the element (Z), i.e. the number of protons, and the mass number (A), equal to the sum of the numbers of protons and neutrons, you can find the number of neutrons (N) using the formula:

N=A-Z

For example, the number of neutrons in an iron atom is:

56 — 26 = 30

isotopes

Varieties of atoms of the same element that have the same nuclear charge but different mass numbers are called isotopes. Chemical elements found in nature are a mixture of isotopes. So, carbon has three isotopes with a mass of 12, 13, 14; oxygen - three isotopes with a mass of 16, 17, 18, etc. Usually given in the Periodic system, the relative atomic mass of a chemical element is the average value of the atomic masses of a natural mixture of isotopes of a given element, taking into account their relative content in nature. The chemical properties of the isotopes of most chemical elements are exactly the same. However, hydrogen isotopes differ greatly in properties due to the dramatic fold increase in their relative atomic mass; they have even been given individual names and chemical symbols.

Elements of the first period

Scheme of the electronic structure of the hydrogen atom:

Schemes of the electronic structure of atoms show the distribution of electrons over electronic layers (energy levels).

The graphical electronic formula of the hydrogen atom (shows the distribution of electrons over energy levels and sublevels):

Graphic electronic formulas of atoms show the distribution of electrons not only in levels and sublevels, but also in orbits.

In a helium atom, the first electron layer is completed - it has 2 electrons. Hydrogen and helium are s-elements; for these atoms, the s-orbital is filled with electrons.

All elements of the second period the first electron layer is filled, and the electrons fill the s- and p-orbitals of the second electron layer in accordance with the principle of least energy (first s, and then p) and the rules of Pauli and Hund.

In the neon atom, the second electron layer is completed - it has 8 electrons.

For atoms of elements of the third period, the first and second electron layers are completed, so the third electron layer is filled, in which electrons can occupy 3s-, 3p- and 3d-sublevels.

A 3s ​​electron orbital is completed at the magnesium atom. Na and Mg are s-elements.

For aluminum and subsequent elements, the 3p sublevel is filled with electrons.

The elements of the third period have unfilled 3d orbitals.

All elements from Al to Ar are p-elements. s- and p-elements form the main subgroups in the Periodic system.

Elements of the fourth - seventh periods

A fourth electron layer appears at the potassium and calcium atoms, the 4s sublevel is filled, since it has less energy than the 3d sublevel.

K, Ca - s-elements included in the main subgroups. For atoms from Sc to Zn, the 3d sublevel is filled with electrons. These are 3d elements. They are included in the secondary subgroups, they have a pre-external electron layer filled, they are referred to as transition elements.

Pay attention to the structure of the electron shells of chromium and copper atoms. In them, a “failure” of one electron from the 4s- to the 3d-sublevel occurs, which is explained by the greater energy stability of the resulting electronic configurations 3d 5 and 3d 10:

In the zinc atom, the third electron layer is completed - all the 3s, 3p and 3d sublevels are filled in it, in total there are 18 electrons on them. In the elements following zinc, the fourth electron layer continues to be filled, the 4p sublevel.

Elements from Ga to Kr are p-elements.

The outer layer (fourth) of the krypton atom is complete and has 8 electrons. But there can only be 32 electrons in the fourth electron layer; the 4d- and 4f-sublevels of the krypton atom still remain unfilled. The elements of the fifth period are filling the sub-levels in the following order: 5s - 4d - 5p. And there are also exceptions related to " failure» electrons, y 41 Nb, 42 Mo, 44 ​​Ru, 45 Rh, 46 Pd, 47 Ag.

In the sixth and seventh periods, f-elements appear, i.e., elements in which the 4f- and 5f-sublevels of the third outside electronic layer are filled, respectively.

4f elements are called lanthanides.

5f elements are called actinides.

The order of filling of electronic sublevels in the atoms of elements of the sixth period: 55 Cs and 56 Ba - 6s-elements; 57 La … 6s 2 5d x - 5d element; 58 Ce - 71 Lu - 4f elements; 72 Hf - 80 Hg - 5d elements; 81 T1 - 86 Rn - 6d elements. But even here there are elements in which the order of filling of electronic orbitals is “violated”, which, for example, is associated with greater energy stability of half and completely filled f-sublevels, i.e. nf 7 and nf 14. Depending on which sublevel of the atom is filled with electrons last, all elements are divided into four electronic families, or blocks:

• s-elements. The s-sublevel of the outer level of the atom is filled with electrons; s-elements include hydrogen, helium and elements of the main subgroups of groups I and II.

• p-elements. The p-sublevel of the outer level of the atom is filled with electrons; p-elements include elements of the main subgroups of III-VIII groups.

• d-elements. The d-sublevel of the preexternal level of the atom is filled with electrons; d-elements include elements of secondary subgroups of groups I-VIII, i.e., elements of intercalary decades of large periods located between s- and p-elements. They are also called transition elements.

• f-elements. The f-sublevel of the third outside level of the atom is filled with electrons; these include the lanthanides and antinoids.

The Swiss physicist W. Pauli in 1925 established that in an atom in one orbital there can be no more than two electrons having opposite (antiparallel) spins (translated from English - “spindle”), i.e. having such properties that can be conditionally imagined as the rotation of an electron around its imaginary axis: clockwise or counterclockwise.

This principle is called Pauli principle. If there is one electron in the orbital, then it is called unpaired, if there are two, then these are paired electrons, that is, electrons with opposite spins. The figure shows a diagram of the division of energy levels into sublevels and the order in which they are filled.

Very often, the structure of the electron shells of atoms is depicted using energy or quantum cells - they write down the so-called graphic electronic formulas. For this record, the following notation is used: each quantum cell is denoted by a cell that corresponds to one orbital; each electron is indicated by an arrow corresponding to the direction of the spin. When writing a graphical electronic formula, two rules should be remembered: Pauli principle and F. Hund's rule, according to which electrons occupy free cells first one at a time and at the same time have the same spin value, and only then they pair, but the spins, according to the Pauli principle, will already be oppositely directed.

Hund's rule and Pauli's principle

Hund's rule- the rule of quantum chemistry, which determines the order of filling the orbitals of a certain sublayer and is formulated as follows: the total value of the spin quantum number of electrons of this sublayer should be maximum. Formulated by Friedrich Hund in 1925.

This means that in each of the orbitals of the sublayer, one electron is first filled, and only after the exhaustion of unfilled orbitals, a second electron is added to this orbital. In this case, there are two electrons with half-integer spins of the opposite sign in one orbital, which pair (form a two-electron cloud) and, as a result, the total spin of the orbital becomes equal to zero.

Other wording: Below in energy lies the atomic term for which two conditions are satisfied.

1. Multiplicity is maximum
2. When the multiplicities coincide, the total orbital momentum L is maximum.

Let's analyze this rule using the example of filling the orbitals of the p-sublevel p- elements of the second period (that is, from boron to neon (in the diagram below, horizontal lines indicate orbitals, vertical arrows indicate electrons, and the direction of the arrow indicates the orientation of the spin).

Klechkovsky's rule

Klechkovsky's rule - as the total number of electrons in atoms increases (with an increase in the charges of their nuclei, or the ordinal numbers of chemical elements), atomic orbitals are populated in such a way that the appearance of electrons in higher-energy orbitals depends only on the principal quantum number n and does not depend on all other quantum numbers. numbers, including those from l. Physically, this means that in a hydrogen-like atom (in the absence of interelectron repulsion) the orbital energy of an electron is determined only by the spatial remoteness of the electron charge density from the nucleus and does not depend on the features of its motion in the field of the nucleus.

Klechkovsky's empirical rule and the sequence of sequences of a somewhat contradictory real energy sequence of atomic orbitals arising from it only in two cases of the same type: for atoms Cr, Cu, Nb, Mo, Ru, Rh, Pd, Ag, Pt, Au, there is a “failure” of an electron with s - sublevel of the outer layer to the d-sublevel of the previous layer, which leads to an energetically more stable state of the atom, namely: after filling the orbital 6 with two electrons s

Everything in the world is made up of atoms. But where did they come from, and what do they themselves consist of? Today we answer these simple and fundamental questions. Indeed, many people living on the planet say that they do not understand the structure of atoms, of which they themselves are composed.

Naturally, the dear reader understands that in this article we are trying to present everything at the most simple and interesting level, therefore we do not “load” with scientific terms. For those who want to study the issue at a more professional level, we advise you to read specialized literature. However, the information in this article can do a good job in your studies and just make you more erudite.

An atom is a particle of matter of microscopic size and mass, the smallest part of a chemical element, which is the carrier of its properties. In other words, it is the smallest particle of a substance that can enter into chemical reactions.

History of discovery and structure

The concept of the atom was known in ancient Greece. Atomism is a physical theory that states that all material objects are made up of indivisible particles. Along with Ancient Greece, the idea of ​​atomism was also developed in parallel in Ancient India.

It is not known whether aliens told the then philosophers about atoms, or they thought of it themselves, but chemists were able to experimentally confirm this theory much later - only in the seventeenth century, when Europe emerged from the abyss of the Inquisition and the Middle Ages.

For a long time, the dominant idea of ​​the structure of the atom was the idea of ​​it as an indivisible particle. The fact that the atom can still be divided, it became clear only at the beginning of the twentieth century. Rutherford, thanks to his famous experiment with the deflection of alpha particles, learned that the atom consists of a nucleus around which electrons revolve. The planetary model of the atom was adopted, according to which electrons revolve around the nucleus, like the planets of our solar system around a star.

Modern ideas about the structure of the atom have advanced far. The nucleus of an atom, in turn, consists of subatomic particles, or nucleons - protons and neutrons. It is the nucleons that make up the bulk of the atom. At the same time, protons and neutrons are also not indivisible particles, and consist of fundamental particles - quarks.

The nucleus of an atom has a positive electrical charge, while the electrons orbiting have a negative charge. Thus, the atom is electrically neutral.

Below is an elementary diagram of the structure of the carbon atom.

properties of atoms

Weight

The mass of atoms is usually measured in atomic mass units - a.m.u. An atomic mass unit is the mass of 1/12 of a free resting carbon atom in its ground state.

In chemistry, to measure the mass of atoms, the concept is used "mol". 1 mole is the amount of a substance that contains the number of atoms equal to Avogadro's number.

The size

Atoms are extremely small. So, the smallest atom is the Helium atom, its radius is 32 picometers. The largest atom is the cesium atom, which has a radius of 225 picometers. The prefix pico means ten to the minus twelfth! That is, if 32 meters is reduced by a thousand billion times, we will get the size of the radius of a helium atom.

At the same time, the scale of things is such that, in fact, the atom consists of 99% of emptiness. The nucleus and electrons occupy an extremely small part of its volume. To illustrate, let's look at an example. If you imagine an atom in the form of an Olympic stadium in Beijing (or maybe not in Beijing, just imagine a large stadium), then the nucleus of this atom will be a cherry located in the center of the field. The orbits of the electrons would then be somewhere at the level of the upper stands, and the cherry would weigh 30 million tons. Impressive, isn't it?

Where did atoms come from?

As you know, now various atoms are grouped in the periodic table. It has 118 (and if with predicted but not yet discovered elements - 126) elements, not counting isotopes. But it was not always so.

At the very beginning of the formation of the Universe, there were no atoms, and even more so, there were only elementary particles, interacting with each other under the influence of enormous temperatures. As a poet would say, it was a real apotheosis of particles. In the first three minutes of the existence of the Universe, due to a decrease in temperature and the coincidence of a whole bunch of factors, the process of primary nucleosynthesis started, when the first elements appeared from elementary particles: hydrogen, helium, lithium and deuterium (heavy hydrogen). It was from these elements that the first stars were formed, in the depths of which thermonuclear reactions took place, as a result of which hydrogen and helium “burned out”, forming heavier elements. If the star was large enough, then it ended its life with the so-called “supernova” explosion, as a result of which atoms were ejected into the surrounding space. And so the whole periodic table turned out.

So, we can say that all the atoms of which we are composed were once part of the ancient stars.

Why does the nucleus of an atom not decay?

In physics, there are four types of fundamental interactions between particles and the bodies they compose. These are strong, weak, electromagnetic and gravitational interactions.

It is thanks to the strong interaction, which manifests itself on the scale of atomic nuclei and is responsible for the attraction between nucleons, that the atom is such a “tough nut”.

Not so long ago, people realized that when the nuclei of atoms split, huge energy is released. The fission of heavy atomic nuclei is the source of energy in nuclear reactors and nuclear weapons.

So, friends, having introduced you to the structure and fundamentals of the structure of the atom, we can only remind you that we are ready to help you at any time. It doesn't matter if you need to complete a diploma in nuclear physics, or the smallest test - the situations are different, but there is a way out of any situation. Think about the scale of the Universe, order a job at Zaochnik and remember - there is no reason to worry.

Option 1

Part A.

A 1. The nucleus of an atom (39 K) is formed

1) 19 protons and 20 electrons 2) 20 neutrons and 19 electrons

3) 19 protons and 20 neutrons 4) 19 protons and 19 neutrons

A 2. The atom of the element phosphorus corresponds to the electronic formula

1) 1S 2 2S 2 2p 6 3S 2 3p 2 2) 1S 2 2S 2 2p 6 3S 2 3p 3 3) 1S 2 2S 2 2p 6 3S 2 3p 4 4) 1S 2 2S 2 2p 6 3S 2 3p 5

A 3. Chemical elements are arranged in order of decreasing their atomic radii

1) Ba, Cd, Sb 2) In, Pb, Sb 3) Cs, Na, H 4) Br, Se, As

A 4. Are the following statements about chemical elements correct?

A. All chemical elements-metals belong to S- and d-elements.

B. Non-metals in compounds exhibit only a negative oxidation state.

A 5. Among the metals of the main subgroup of group II, the most powerful reducing agent is

1) barium 2) calcium 3) strontium 4) magnesium

A 6. The number of energy layers and the number of electrons in the outer energy layer of the chromium atom are, respectively,

A 7. Higher chromium hydroxide exhibits

A 8. The electronegativity of elements increases from left to right in the series

1) O-S-Se-Te 2) B-Be-Li-Na 3) O-N-P-As 4) Ge-Si-S-Cl

A 9. The oxidation state of chlorine in Ba(ClO 3) 2 is

1) +1 2) +3 3) +5 4) +7

A 10. The element arsenic belongs to

Answers to the task B1-B2

IN 1. The increase in the acidic properties of higher oxides occurs in the series:

1) CaOSiO 2 SO 3 2) CO 2 Al 2 O 3 MgO 3) Li 2 OCO 2 N 2 O 5

4) As 2 O 5 P 2 O 5 N 2 O 5 5) BeOCaOSrO 6) SO 3 P 2 O 5 Al 2 O 3

IN 2. Set a match.

Core Composition Electronic formula

A. 7 p + 1, 7 n 0 1 1. 2S 2 2p 3

B. 15 p + 1, 16 n 0 1 2. 2S 2 2p 4

B. 9 p + 1 , 10 n 0 1 3. 3S 2 3p 5

D. 34 p + 1, 45 n 0 1 4. 2S 2 2p 5

From 1. Write the formula for the higher oxide and higher bromine hydroxide. Write down the electronic configuration of the bromine atom in the ground and excited state, determine its possible valencies.

Write the electronic formulas of the bromine atom in the maximum and minimum powers.

Examination No. 1 on the topic "Structure of the atom"

Option 2

Part A. Choose one correct answer

A 1. The number of protons, neutrons and electrons of the 90 Sr isotope, respectively, is

1. 38, 90, 38 2. 38, 52, 38 3. 90, 52, 38 4. 38, 52,90

A 2. The electronic formula 1S 2 2S 2 2p 6 3S 2 3p 6 4S 1 corresponds to the atom of the element

1. sulfur 2. bromine 3. potassium 4. manganese

A 3. Elements are arranged in order of decreasing atomic radius

1) boron, aluminum, gallium 3) boron, carbon, silicon

2) potassium, sodium, lithium 4) krypton, xenon, radon

A 4. Are the following judgments about changing the properties of elements in a series correct?

Be-Mg-Ca-Sr-Ba?

A. Metallic properties are enhanced.

B. The radius of atoms and the number of valence electrons do not change.

1) only A is true 2) only B is true 3) both judgments are correct 4) both judgments are wrong

A 5. Among the non-metals of the third period, the most powerful oxidizing agent is

1) phosphorus 2) silicon 3) sulfur 4) chlorine

A 6. The number of energy layers and the number of electrons in the outer energy layer of a manganese atom are, respectively,

1) 4, 2 2) 4, 1 3) 4, 6 4) 4, 5

A 7. Higher manganese hydroxide exhibits

1) acidic properties 3) basic properties

2) amphoteric properties 4) does not show acid-base properties

A 8. The electronegativity of elements decreases from left to right along the row

1) O-Se-S-Te 2) Be-Be-Li-H 3) O-N-P-As 4) Ge-Si-S-Cl

A 9. The oxidation state of nitrogen in Ba(NO 2) 2 is

1) +1 2) +3 3) +5 4) +7

A 10. The element manganese belongs to

1) s-elements 2) p-elements 3) d-elements 4) transition elements

Answers to the task B1-B2 is the sequence of digits that corresponds to the numbers of the correct answers.

IN 1. The increase in the basic properties of higher hydroxides occurs in the series of the elements that form them:

1) MgAl ) AsР 3) PSCl

4) BBeLi 5) MgCaBa 6)CaKCs

IN 2. Set a match.

Core Composition Electronic formula

A. 19 p + 1, 20 n 0 1 1. 4S 1

B. 20 p + 1, 20 n 0 1 2. 4S 2

B. 14 p + 1, 14 n 0 1 3. 5S 1

D. 35 p + 1, 45 n 0 1 4. 4S 2 4p 5

When completing task C 1, write down in detail the course of its solution and the result obtained.

From 1. Write the formula for the higher oxide and higher arsenic hydroxide. Write down the electronic configuration of the arsenic atom in the ground and excited state, determine its possible valencies.

Write the electronic formulas of the arsenic atom in the maximum and minimum powers.

Test No. 1 “Structure of the atom. Periodic system. Chemical formulas»

Zakirova Olisya Telmanovna – teacher of chemistry.

MBOU "Arskaya average general educational school № 7 "

Purpose: To check the consistency, strength, depth of knowledgeon the topic “The structure of the atom. Periodic system. Chemical formulas». To control the degree of assimilation by students of knowledge about the structure of the atom, the ability to characterize the element by position in the PSCE, to determine the molecular weight of compounds.

Stage 1. Organizing time. 1. Greeting.

2. Organization of jobs.

3. Announcement of the purpose of the lesson to students

Setting the goal of the lesson:

Repetition, generalization and systematization of concepts.PZ and PSE D. I. Mendeleev

Stage 2: Repetition, generalization and systematization of concepts

Option 1.

1. What determines the place of a chemical element in D.I. Mendeleev's PSCE?

A) the number of electrons in an atom; B) the number of electrons in the outer level; C) the number of neutrons in the atomic nucleus;

D) the number of protons in the atomic nucleus; E) there is no correct answer.

2. What determines the properties of chemical elements? A) the value of the relative atomic mass; B) the charge of the atomic nucleus; C) the number of electrons at the external level; D) the number of electrons in the atom; E) there is no correct answer.

3. How can you determine the number of electronic levels in an atom of any chemical element?

4. How can you determine the number of electrons on the outer layer of the atoms of the elements of the main subgroups?

A) by period number; B) by group number; C) by row number; D) there is no correct answer.

5. How does the radius of an atom change with an increase in the ordinal number of an element in a period?

A) increases; B) decreases; C) does not change; D) there is no pattern in the changes.

6. An atom of which of the following elements has the largest radius?

A) beryllium; B) boron; B) carbon; D) nitrogen.

7. Find the molecular weightCO2 ; H2 SO4

Option 2.

1. How do the properties of chemical elements change in a period with an increase in the charge of the nucleus?

A) metallic properties are enhanced; B) metallic properties are periodically repeated;

C) non-metallic properties are enhanced; D) there is no correct answer.

2. Which element has the most pronounced metallic properties? A) silicon; B) aluminum; C) sodium; D) magnesium.

3. How do the properties of elements in the main subgroups of the periodic system change with increasing nuclear charge?

A) metallic properties weaken; B) metallic properties do not change;

C) non-metallic properties do not change; D) there is no correct answer.

4. Which element has the most pronounced non-metallic properties? A) sulfur; B) oxygen; C) selenium; D) tellurium.

5. What determines the place of a chemical element in D.I. Mendeleev's PSCE? A) the mass of the atom; B) the charge of the atomic nucleus;

C) the number of electrons in the outer level; D) the number of electronic levels of the atom; E) there is no correct answer.

6. By the number of the period in which the chemical element is located, one can determine: A) the number of electrons in the atom;

B) the number of electrons in the outer electronic level; C) the highest valency of the element;

D) the number of electronic levels in an atom; E) there is no correct answer.

7. Find the molecular weightCO ; H2 SO3

Option 3.

1. What determines the properties of a chemical element? A) the number of electrons in an atom; B) the number of electronic levels in an atom; C) the number of neutrons in an atomic nucleus; D) there is no correct answer.

2. By the number of the group in which the atom is located, you can determine: A) the number of electrons in the atom;

B) the number of electrons in the outer electronic level in an atom of any element in the group;

C) the number of electrons in the outer electronic level in the atom of the element of the main subgroup of this group;

D) the number of electronic levels in an atom; E) there is no correct answer.

3. How does the radius of an atom change in a period with an increase in the ordinal number of the element?

A) does not change; B) increases; C) decreases; D) repeats periodically.

4. How do the properties of chemical elements change in a period with an increase in the charge of the nucleus? A) metallic properties weaken; B) metallic properties are periodically repeated; C) non-metallic properties weaken;

D) non-metallic properties are periodically repeated; E) there is no correct answer.

5. How the properties of elements change in the main subgroups of PSCE D.I. Mendeleev with an increase in the charge of the nucleus?

A) metallic properties are enhanced; B) non-metallic properties are enhanced;

C) properties do not change; D) there is no correct answer.

6. Which element has the most pronounced non-metallic properties?

A) germanium; B) arsenic; C) bromine; D) selenium.

7. Find the molecular weightH2 O ; H3 PO4

Stage 3: Summing up the lesson.