Question

which pair of elements is most likely to form a molecule? sulfur and bromine calcium and oxygen sodium and calcium magnesium and hydrogen

Explanation:

Molecules are formed by the sharing of electrons between non - metals (covalent bonding). Sulfur (S) and bromine (Br) are both non - metals. Calcium (Ca) and oxygen (O) form an ionic compound (CaO). Sodium (Na) and calcium (Ca) are metals and do not form a molecular compound. Magnesium (Mg) and hydrogen (H) form an ionic compound (MgH₂ in some cases, but it's more of a polar covalent - like in metal - hydride context which is not a typical molecule as in covalent non - metal - non - metal).

Answer:

Sulfur and bromine