Chemistry

How many electrons should be shown in the Lewis symbol for hydrogen?

1

Aluminum and oxygen

Al2O3

Barium and fluorine

BaF2

Boron trifluoride (BF3 ) is used as a catalyst in many organic synthesis reactions. What type of bonding occurs between the atoms of a BF3 molecule?

Covalent

Cesium and chlorine

CsCl

What type of bonding occurs in zinc(II) chloride, ZnCl2 ? ionic

Ionic

Lithium and nitrogen

Li3N

What type of bonding occurs in a sample of pure cobalt, Co? In other words, how is one cobalt atom held to another cobalt atom? metallic

Metallic

If this pattern of ions was extended indefinitely in two dimensions, would the lattice energy be positive or negative?

Positive

Which colored balls must represent chloride ions?

The larger green balls represent Cl− anions.

Which colored balls must represent sodium ions?

The smaller purple balls represent Na+ cations.

Determine which ones possess noble-gas configurations.

•Sr2+ •Se2− •Br−