If you were provided a list of chemical formulas (ex: NaCl, CO 2 CaCl 2 , SO 3 ) just the formula, how might you identify which are and which are covalent?

See Explanation

Explanation:

The question is asking us about how to determine which compounds are ionic and which compounds are covalent.

First, we must understand that ionic compounds are formed between metals and nonmetals having a large difference in electronegativity.

Secondly, covalent compounds are mostly formed between atoms of nonmetal elements.

If we keep these things in mind, we can see that compounds such as NaCl and CaCl2 are ionic while CO2 and SO3 are covalent.

petroleum? coal maybe?

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6