Structural particles of matter - Atomic number - Mass number - Isotopes:

 Structural particles of matter - Atomic number - Mass number - Isotopes:

Structural particles of matter:

Each body is composed of infinitely small particles (almost negligible), called structural particles or building blocks of matter. These particles are: atoms, molecules and ions.

Atoms - Molecules - Ions:

Molecule: is the smallest part of a defined substance (compound or element) that can exist freely, maintaining the properties of the matter from which it comes. Molecules are groups of atoms with a defined geometric arrangement in space (image 1.1).

1.1

Atom: 

It is the smallest particle of an element, which can take part in the formation of chemical compounds.

 

Individuality of an element: 

number that indicates how many atoms the molecule of an element is made of.

The individuality of the element is indicated as an index in the symbol of the element. Below are the individualities of the most important elements.

MONOATOMICS: Noble gases: He, Ne, Ar, Kr, Xe, Rn, and steaming metals.

Also, in the chemical equations the elements C, S and P. are written as monoatomic

DIAMATIC: H2, O2, N2, F2, Cl2, Br2, I2.

TRIATOMICS: O3

.

QUARTERLY: P4, As4, Sb4.

Ions:

Ions are either charged atoms (monoatomic ions), e.g. Na +, Ca2 +, S2-, Cl- or charged atomic assemblies (polyatomic ions), e.g. NH4 +, CO32-, H2PO4- 

.

Ions that have a positive electric charge are called cations, e.g. Na +, and those that have a negative electric charge are called anions, e.g. Cl-.

 Ions are the building blocks of ionic or heteropolar compounds.

Atomic number (G):

 It is the number of protons in the atomic nucleus of an element. This number determines the type of person, ie it is a kind of identity for him.

The value of Z also indicates the number of electrons. Do not forget that in the atom the number of electrons is equal to the number of protons (and vice versa), so that the atom is electrically neutral, which (the number of protons) is equal to the atomic number (Z) (and vice versa). But when there is an ion, the electrons are NOT equal to the protons. 

e.g._ the atom of calcium (Ca2 +) has atomic number (G) 20. So it has 20 protons (p), but 18 electrons, because it expelled 2. it has + eliminated and when it has - it takes up electrons).

Mass number (A):

It is the number of protons and neutrons in an atom's nucleus.

 Type: Α = Ζ + Ν

The atom of an element X is denoted by:

Isotopes:

 Named the atoms that have the same atomic but different mass number.