CHEMICAL BONDING

CHEMICAL BONDING

Lewis’s theory follows:

1. Electrons, especially those of the outermost (valence) electronic shell, play a fundamental role in chemical bonding.

2. In some cases, electrons are transferred from one atom

to another. Positive and negative ions are formed and

attract each other through electrostatic forces called ionic

bonds.

Gilbert N. Lewis :

Gilbert N. Lewis published a paper about chemical bonding in 1916 with the title «The atom and the molecule» (Lewis, 1916).

He describes the concepts of electron arrangements.

His theory about bonding is based on the number of outer shell electrons (valence electrons) in an atom.

He suggested that when two atoms shares a pair of

electrons, they form a chemical bond. Lewis dot diagrams

are still in use today.

Lewis

Gilbert N. Lewis suggested that when two atoms shares a pair of electrons, they form a chemical bond.

Lewis dot diagrams are still in use today.

Lewis Symbols and Lewis Structures

A Lewis symbol consists of a chemical symbol to

represent the nucleus and core (inner-shell) electrons of an atom, together with dots placed around the

symbol to represent the valence(outer-shell) electrons.

Thus, the Lewis symbol for silicon, which has the

electron configuration , is [Ne]3s ² 3p ²

Octet Rule

Most elements follow the octet rule in chemical bonding,

which means that an element should have contact to

eight valence electrons in a bond or exactly fill up its

valence shell. Having eight electrons total ensures that

the atom is stable.

Octet Rule

Having eight electrons total ensures that the atom is stable. The noble gases have the most stable configuration (full octet, no charge), so they have no reason to react and change their configuration. They rarely form compounds.

All other elements attempt to gain, lose, or share

electrons to achieve a noble gas configuration.