Chemistry

Chemical bonds


Atoms are hardly left alone in nature. They tend to come together, thus forming everything that exists today.

Some atoms are stable, that is, little reactive. Others can not be isolated, they need to connect to other elements. The forces that hold atoms together are fundamentally electrical in nature and are called chemical bonds.

Every bond involves the movement of electrons in the outermost layers of atoms, but never reaches the nucleus.

Noble gas stability

Of all known chemical elements, only 6, noble or rare gases, are found in nature as isolated atoms. The others are always connected to each other in different ways, in various combinations.

Noble gases are found in nature in the form of isolated atoms because they have the last layer of the complete electrosphere, ie with 8 electrons. Even 2-electron helium is complete because level K only allows a maximum of 2 electrons.

Octet Rule - Chemical elements must always contain 8 electrons in the last electronic layer or valence layer. In the K layer there can be a maximum of 2 electrons. In this way the atoms are stable, with the same configuration as the noble gases.

Note the electronic distribution of the noble gases in the following table:

NAME

SYMBOL

Z

K

L

M

N

O

P

Q

HELIUM

He

2

2

-

-

-

-

-

-

NEONIO

Huh

10

2

8

-

-

-

-

-

ARGON

Air

18

2

8

8

-

-

-

-

KRYPTON

Kr

36

2

8

18

8

-

-

-

XENON

X and

54

2

8

18

18

8

-

-

RADON

Rn

86

2

8

18

32

18

8

-

The stability of the noble gases is due to the fact that they have the last complete layer, that is, with the maximum number of electrons this layer can contain while the last one. Atoms of other chemical elements, to be stable, must acquire, through chemical bonds, electrospheres equal to those of noble gases.

There are three types of chemical bonds:

- Ionic bond - loss or gain of electrons.
- Covalent bond - electron sharing.
- Metal connection - neutral atoms and cations plunged into a cloud of electrons.