Kinetic Theory of Matter

Electrons occupy orbits with definite energy level of an atom, as suggested by Neils Bohr.

These orbits with definite energy level are known as the shell.

Every single shell is capable of holding up to certain amount of electrons

The first shell can hold up to two electrons. This is called a duplet.

The second shell can hold up to eight electrons. This is called an octet.

The third shell can hold up to eighteen electrons.

However, with the third shell, when eight electrons are present, extra stability is gained. The additional electrons go into the fourth shell before the third shell is completely filled.

Finding the electron arrangement of an atom

The electrons in the outermost shell of an atom

Elements with the same number of valence electron have the same chemical properties.

The electrons in the outermost shell of an atom are called valence electrons.