Question

the oxidation number of an atom in an elemental substance is __. the sum of oxidation numbers for all atoms in a molecule or polyatomic ion __ the charge on the molecule or ion. one; equals zero; is greater than one; is less than zero; equals clear my selection

Explanation:

The oxidation number of an atom in an elemental substance is zero because the atoms in an element have no electronegativity difference. For a molecule or poly - atomic ion, the sum of oxidation numbers of all atoms equals the charge on the molecule or ion. This is a fundamental rule in oxidation - number determination in chemistry.

Answer:

D. zero; equals