Question

test: covalent compounds
covalent bonds form between and
metals nonmetals

Explanation:

Covalent bonds involve the sharing of electrons. Non - metals have relatively high electronegativities. When two non - metals come together, neither has a strong tendency to completely lose or gain electrons. Instead, they share electrons to achieve a more stable electron configuration (usually an octet, similar to noble gases). Metals, on the other hand, tend to form ionic bonds (by losing electrons) or metallic bonds (in the case of pure metals).

Answer:

nonmetals and nonmetals