Compared to the average diameter of a hydrogen atom, the average diameter of a helium atom is
A) smaller.
B) larger.
C) about the same.

Question

Quizplus · Accepted Answer

The average diameter of a helium atom is smaller than that of a hydrogen atom because helium's two electrons are more strongly attracted to its nucleus, which has two protons, compared to hydrogen's single proton. This stronger attraction pulls the electrons closer, resulting in a smaller average diameter.

Compared to the Average Diameter of a Hydrogen Atom, the Average