Atoms and Molecules. How an atom differs from a molecule How do atoms of different chemicals differ?

In translation, "atom" means indivisible. It is named so because for a long time it was considered the smallest part of the substance. But the further development of science has shown that this is not so. So, let's figure out what an atom consists of and how the atoms of different elements differ.

Atom structure

To date, science knows 126 species chemical elements... The general plan of the structure of their atoms is the same. Each of them has a nucleus, consisting of protons and neutrons, around which electrons revolve. Electrons are negatively charged particles. When they rotate around the nucleus, an electron cloud is formed.

Protons are positively charged particles. At rest, an atom contains the same number of protons and electrons, therefore such a chemical element has no electric charge. However, in the process of reactions, it can give an electron to other elements, turning into a positively charged particle, or take them away, becoming a negatively charged particle. Neutrons do not carry any charge, but they affect the mass of the element. A unifying name was invented for protons and neutrons - nucleons.

Atoms of various elements

The atoms of various elements differ from each other in the number of protons in the nucleus. The number of electrons can change, but the number of protons never. How many protons are in the nucleus, you can find out by the ordinal number of the element in the periodic table of Mendeleev. Hydrogen (No. 1) has 1 electron and 1 proton at rest, lithium
(No. 3) has 3 electrons and 3 protons, carbon (No. 6) has 6 electrons and 6 protons.

Since the number of protons in different atoms is different, their masses also differ. The mass of an element is mainly formed by protons and neutrons, because the weight of electrons is negligible. But even atoms of the same element may have different weights due to the different number of neutrons in the nucleus. Atoms in which the number of neutrons differs from the number of protons are called isotopes. For example, in nature there are carbon atoms C12 (6 protons and 6 neutrons), C13 (6 protons and 7 neutrons) and other varieties with a neutron content of 2 to 16.

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What is the difference between the concepts "atom" and "molecule"? and got the best answer

Answer from Sunrise [expert]
an atom is smaller, one molecule can have several atoms (example - 2 hydrogen atoms and one oxygen atom \u003d water molecule)

Answer from Diana Mamina[guru]
A molecule is made up of atoms.

Answer from NOT[guru]
In addition to common places, he is also a native.

Answer from Air[newbie]
an atom is an electrically neutral system of interacting elements, consisting of a nucleus and electrons. , and a molecule is a compound consisting of 2 or more atoms

Answer from Durchlaucht furst[guru]
Atom (other Greek ἄτομος - indivisible) is the smallest part of a chemical element that is the carrier of its properties. An atom consists of an atomic nucleus and an electron cloud surrounding it. The nucleus of an atom consists of positively charged protons and electrically neutral neutrons, while the surrounding cloud consists of negatively charged electrons. If the number of protons in the nucleus coincides with the number of electrons, then the atom as a whole is electrically neutral. Otherwise, it has some positive or negative charge and is called an ion. Atoms are classified by the number of protons and neutrons in the nucleus: the number of protons determines the belonging of an atom to a certain chemical element, and the number of neutrons determines the isotope of that element.
Atoms of different types in different quantities, connected by interatomic bonds, form molecules.
The concept of the atom as the smallest indivisible part of matter was first formulated by ancient Indian and ancient Greek philosophers (see: atomism). In the XVII and XVIII centuries chemists were able to experimentally confirm this idea, showing that some substances cannot be further decomposed into their constituent elements using chemical methods. However, in the late 19th and early 20th centuries, physicists discovered subatomic particles and the compound structure of the atom, and it became clear that the atom is not really "indivisible."
Molecule (Novolatinsk molecula, diminutive from Latin moles - mass) is the smallest particle of a substance that carries its chemical properties.
A molecule consists of two or more atoms, characterized by the number of atomic nuclei and electrons included in it, as well as a certain structure.
It is usually assumed that the molecules are neutral (do not carry electric charges) and do not carry unpaired electrons (all valencies are saturated); charged molecules are called ions, molecules with a multiplicity other than unity (i.e., with unpaired electrons and unsaturated valences) are called radicals.
Molecules made up of hundreds or thousands of atoms are called macromolecules. The structural features of molecules determine the physical properties of a substance consisting of these molecules.

Answer from Mariyam Abdullah[newbie]
also atoms have an electric charge, while the molecule is neutral

Answer from Murvat Kazimov[newbie]
an atom is what a molecule is made of

Atom and ion are elementary particles of chemical elements. These particles are carriers of the properties of the elements. They differ in charges: the atom is neutral, and the ion is positively or negatively charged.

Definition

Atom- an electrically neutral microscopic particle of a chemical element that determines its properties. The center of an atom is a positively charged nucleus surrounded by an electron cloud, along which electrons move in orbitals. Atoms, adding or donating electrons, turn into ions.

Jonah - microscopic electrically charged, monoatomic or polyatomic and chemically active particles. They have a positive (cations) or negative (anions) charge. Ions are formed from atoms or groups of atoms that acquire electrons or, conversely, lose them.

Ions are independent particles found in any state of aggregation. They are found in gases (in the atmosphere), in crystals, in liquids (both solutions and melts) and in plasma (interstellar space.)

Ions in chemical reactions are able to interact with each other, with molecules and atoms. In solutions, these active particles are formed during electrolytic dissociation and determine the properties of electrolytes.

Comparison

An atom is always electrically neutral, an ion, on the contrary, is a charged particle. For atoms, the outer energy levels are, as a rule, incomplete (the exception is the group of noble gases). For ions, the outer levels are completed.

The ion, in contrast to the atom, is not capable of possessing the properties of a simple substance. For example, metallic potassium enters into a violent reaction with water, the products of which are hydrogen and alkali. And the potassium ions present in the composition of potassium salts do not have similar properties. Chlorine is a yellow-green poisonous gas, and its ions are non-toxic and colorless.

The color of copper is red, and its ions in solutions acquire a blue color. Iodine crystals are gray, vapors are violet, an alcohol solution is red-brown in color, mixed with starch, it gives a blue coloration. Iodine ions cannot change the color of starch, they are colorless.

Conclusions site

1. Atoms and ions of one chemical element have a different number of electrons.
2. The charge of atoms is zero, for ions it can be positive or negative.
3. Ions and atoms have different redox properties.

All the matter that we see around us is made up of various atoms. Atoms differ from each other in structure, size and mass. There are more than 100 types of different atoms, more than 20 types of atoms were produced by man and do not occur in nature, as they are unstable and decay into simpler atoms.

However, even atoms belonging to the same species may differ slightly from each other. Therefore, there is such a thing as a chemical element - these are atoms of the same type. They all have the same nuclear charge, that is, the same number of protons.

Each chemical element has a name and designation in the form of one or two letters from the Latin name of this element. For example, the chemical element hydrogen is denoted by the letter H (from the Latin name Hydrogenium), chlorine - Cl (from Chlorum), carbon - C (from Carboneum), gold - Au (from Aurum), copper - Cu (from Cuprum), oxygen - O (from Oxigeium).

The existing chemical elements are listed in the Periodic Table of Mendeleev. Often they speak of it as a system (periodic table), because there are certain strict rules according to which this or that element is placed in its cell of the table. Regular changes in the properties of elements are observed in the rows and columns of the periodic table. Thus, each element in the table has its own number.

The atoms of chemical elements do not change as a result of chemical reactions. The set of substances formed by atoms changes, but not themselves. For example, if, as a result of a chemical reaction, carbonic acid (H 2 CO 3) decomposed into water (H 2 O) and carbon dioxide (CO 2), then no new atoms were formed. Only the connections between them have changed.

Thus, an atom can be defined as the smallest, chemically indivisible particle of matter.

The most abundant element in the universe is hydrogen, followed by helium. These are the simplest chemical elements in structure. The rest of the chemical elements account for about 0.1% of all atoms. However, the atoms of other chemical elements have a greater mass than the atoms of hydrogen and helium. Therefore, if we express the content of the remaining chemical elements in the Universe in mass percent, then they will account for 2% of the mass of all matter in the Universe.

On Earth, the abundance of chemical elements is very different if you consider the entire Universe. Oxygen (O) and silicon (Si) predominate on Earth. They account for about 75% of the Earth's mass. Next come in descending order aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), magnesium (Mg), hydrogen (H) and many other elements.

Many centuries ago, people guessed that any substance on earth consists of microscopic particles. Some time passed, and scientists proved that these particles really exist. They were called atoms. Usually atoms cannot exist separately and are combined into groups. These groups are called molecules.

The very name "molecule" comes from the Latin word moles, meaning heaviness, lump, bulk, and the diminutive suffix - cula. Previously, instead of this term, the word "corpuscle" was used, literally meaning "small body." In order to find out what a molecule is, let's turn to explanatory dictionaries. Ushakov's dictionary says that this is the smallest particle that can exist autonomously and has all the properties of the substance to which it belongs. Molecules and atoms surround us everywhere, and although they cannot be felt, everything we see is in fact their giant clusters.

Example with water

The best way to explain what a molecule is is with the example of a glass of water. If you pour half out of it, then the taste, color and composition of the remaining water will not change. It would be strange to expect something different. If you cast half again, the amount will decrease, but the properties will again remain the same. Continuing in the same spirit, we end up with a small droplet. It can still be divided with a pipette, but this process cannot be continued indefinitely.

Ultimately, you will get the smallest particle, the remainder of the division of which will no longer be water. In order to imagine what a molecule is and how small it is, try to guess how many molecules are in one drop of water. What do you think? Billion? One hundred billion? In fact, there are about a hundred sextillons there. This is the number that has twenty-three zeros after one. Such a value is difficult to imagine, so we will use a comparison: the size of one is smaller than a large apple by as many times as the apple itself is smaller. Therefore, it cannot be seen even with the most powerful optical microscope.

and atoms

As we already know, all microscopic particles, in turn, are composed of atoms. Depending on their number, the orbits of the central atoms and the type of bonds, the geometric shape of the molecules can be different. For example, human DNA is twisted in the form of a spiral, and the smallest particle of ordinary table salt looks like If a molecule is somehow taken away several atoms, its destruction will occur. In this case, the latter will not go anywhere, but will be part of another microparticle.

After we figured out what a molecule is, let's move on to the atom. Its structure is very similar to a planetary system: in the center is a nucleus with neutrons and positively charged protons, and electrons revolve around in different orbits. In general, the atom is electrically neutral. In other words, the number of electrons is equal to the number of protons.

We hope our article turned out to be useful, and now you no longer have questions about what a molecule and an atom are, how they work and how they differ.