Why are ores so valuable? (a) They are sources of naturally occurring gold. (b) Metals can be efficiently extracted from them. (c) They tend to occur in scenic mountainous regions. (d) They hold many...

Why are ores so valuable?

(a) They are sources of naturally occurring gold.

(b) Metals can be efficiently extracted from them.

(c) They tend to occur in scenic mountainous regions.

(d) They hold many clues to Earth’s natural history.

When nitrogen and fluorine combine to form a molecule, the most likely chemical formula is:

(a) N₃F.

(b) N₂F.

(c) NF₄.

(d) NF.

(e) NF₃.