Honors Chemistry-Bonding and Lewis Structures

*Ionic Bonding

Occurs when electrons are transferred between

atoms. Formed by the attraction between a metal and

nonmetal

Cation

Formed when the metal donates one or more electrons to the nonmetal

Anion

Formed when a nonmetal accepts one or more electrons

*"CO"valent Bonding

Occurs when pairs of electrons are shared between atoms.When atoms have different electronegativities, these

electrons are shared "unfairly".

Types of bonds:

- Single: 2 electrons shared

- Double: 4 electrons shared

- Triple: 6 electrons shared

Octet Rule

Elements prefer to have eight valence electrons in their outer

shells. Hydrogen and Helium are exceptions.

G. N. Lewis

Created the Lewis Dot Structure. Kept track of electrons.

*Lewis Symbols

The Lewis symbol for an element consists of the chemical symbol as well as a dot for each valence electron.

Ionic Bodning

Transfer of electrons from one atom to another

Covalent Bonding

sharing of

electrons between two atoms

Steps for writing Lewis Structures

1. Add up the valence electrons for all atoms in

the compound. (Be careful to add or subtract

electrons for ions)

2. Place the least electronegative element at

the center (except for hydrogen)

3. Add SINGLE covalent bonds to connect the

atoms.

4. Add lone (unshared) pairs to the outer atoms.

5. Add lone pairs to the center atom.

6. Check all atoms for octet rule (having 8

electrons, except for H and He). If necessary,

move electrons to create double or triple bonds.

7. If applicable, draw the charge of the ion. For a

polyatomic ion, put the whole Lewis structure in

brackets first.

A lone pair is any 2 electrons not in a covalent bond

Sulfate ion

• SO42̶

• 6 + (6 x 4) + 2= 32 valence electrons

Ammonium ion

• NH4+

• 5 + (1 x 4) - 1 = 8 valence electrons

Carbon

• C

• 4 valence electrons