Please help thank you

YOUR QUERY :

which of the following statements BEST describes the difference between an atom and an ion ?

well the correct answer is

d. An atom contains equal numbers of protons and electrons whereas an ion contains unequal numbers of protons and electrons .

Explanation:

A charged atom is known as an ion, well it can be negative as well as positive charge.

if atom has more protons than electrons then it get positively charged and known as cationif the atom has more electrons that the number of protons then the atom get negatively charged and known as anion

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.