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

Your a cation that has a smaller radius than the atom.

When you remove electrons from an atom, the atom becomes an ion that is positively charged. Cations are defined to be ions that are positively charged, so it must be a cation.

decrease in number of electrons surrounding nucleus while maintaining the positive charge from nucleus means

- less electrostatic repulsion between electrons (opposites repel, so there are less opposites to do the repelling)
- the volume due to the electrons  decrease

the atomic radius gets smaller.

Feel free to drop your sc in comments if you want more help lol

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.