Question

how many electrons are represented by a single dash between two nonmetals?
two are represented.
one is represented.
four are represented.
none, they transfer electrons.

Explanation:

When two non - metals form a covalent bond, a single dash (a single covalent bond) represents a pair of electrons. A pair means two electrons. Non - metals share electrons in covalent bonds (as opposed to transferring electrons like in ionic bonds between metals and non - metals).

Answer:

Two are represented.