Answer:
Hello Friend, I've done my personal research, if the answer that's provided is incorrect, my apologies.
A. Oxygen and Sulfur.
Explanation: There are about 10 non metal elements on the periodic table. The pair (Oxygen and Sulfur) are both non metal.
Ice is less dese than water
Ok the first one (C) for all of the answers is 6 and for the seconds one (Ca) the answers are 20
Answer:
You didn't list the compounds it gave you so i cant cross check them to see it they are ionic bonds( which is the chemical bonding is formed between metal and nonmetal)
if you reply with the compounds it list I will be happy to check for you