1) Oxygen and boron are in the same period . When they form a compound----- is written first.Phosphorus and arsenic are the same group. When they form a compound------is written first.

A) oxygen/phosphorus
B)oxygen/arsenic
C)boron/phosphorus
D)boron/arsenic
answer is D

2) The ionic compound cacl2 would be correctly named.

A) calcium chloride
B)monocalcium dichloride
C)calcium(I)chloride
D)all of the above

answer is A

See your post above.