54) when an atom gains electrons, it is a) reduced b) oxidized c) ionic d) an isotope e) radioactive 55)…

54) when an atom gains electrons, it is a) reduced b) oxidized c) ionic d) an isotope e) radioactive 55) which of the following cannot exist as a single - pair of atoms? a) oxygen b) molecular nitrogen c) sodium chloride d) a and b e) b and c

54) when an atom gains electrons, it is a) reduced b) oxidized c) ionic d) an isotope e) radioactive 55) which of the following cannot exist as a single - pair of atoms? a) oxygen b) molecular nitrogen c) sodium chloride d) a and b e) b and c

Answer

Explanation:

Step1: Recall oxidation - reduction concept

Oxidation is the loss of electrons and reduction is the gain of electrons.

Step2: Analyze the options

When an atom gains electrons, it is reduced according to the definition of reduction - oxidation reactions.

Answer:

A. reduced

Explanation:

Step1: Recall atomic bonding concepts

Oxygen can exist as O₂ (a molecule with a double - bond between two oxygen atoms), nitrogen exists as N₂ (a molecule with a triple - bond between two nitrogen atoms), and sodium chloride is an ionic compound made up of Na⁺ and Cl⁻ ions and not a single pair of atoms.

Step2: Determine the answer

Sodium chloride cannot exist as a single pair of atoms.

Answer:

C. sodium chloride