When electrons are removed from the outermost shell of a calcium atom, the atom becomes an anion that has a larger radius than the atom. an anion that has a smaller radius than the atom. a cation that has a larger radius than the atom. a cation that has a smaller radius than the atom.

a cation that has a smaller radis than the atom

Explanation:

When an atom loses or gains an electron, it gets a charge because the number of protons and electrons are no longer balanced.

When an atom gains an electron, there would be more electrons than protons and would then be negatively charged. This is when it becomes an anion.

When an atom loses an electron, there would be less electrons than protons, so that means it will be positively charged. This is what you call a CATION.

Now the reason the radius becomes smaller is because the protons will have a stronger pull on the electrons, pulling it closer to the nucleus.  

the answer would be a