Chapter 9 Preview Jeopary

Vocabulary

100

Ions

species with an overall charge

200

Covalent bond

two atoms share a pair of electrons

300

Octet rule

atoms are stabilized by having 8 electrons in their valence shell

400

Lewis structure

shows valence structures and covalently bonded atoms

500

What is the equation for formal charge?

formal charge of an atom = (valence electrons in the neutral atom) - (number of covalent bonds) - (number of unshared electrons)

How Many Valence Electrons Does this Element Have?

100

Na

1

200

O

6

300

Ne

8

400

Cl

7

500

Fe

Hint: 1s²2s²2p⁶3s²3p⁶4s²3d⁶

Answer: 2

Lewis Stuctures

100

What is the first step in drawing a Lewis structure?

Determine the number of total valence electrons for the molecule. For anions, add additional electrons. For cations, subtract electrons.

200

What is the second step in drawing a Lewis structure?

Frame the structure through sharing pairs of electrons. 

All atoms in the molecule are connected by a pair of bonding electrons. The central atom is typically towards the bottom-left of the periodic table. Add hydrogens last since it can only make one bond.

300

What is the third step in drawing a Lewis structure?

Complete the octets by adding nonbonding pairs of electrons. Start with outer atoms, adding lone pair electrons

400

What is the fourth step in drawing a Lewis structure?

Assign remaining electrons (if any) to the central atom. If not enough electrons remain, try double or triple bonds. The goal is that every atom has a full octet.

500

What is the fifth step in drawing a Lewis structure?

Assign formal charges if necessary.