5. What is the charge of an atom that has lost four electrons? *

+4

Explanation:

An atom is considered to be neutral before losing or gaining any electrons. They are neutral in charge because they initially have the same number of protons (with charge of +1 each) and electrons (with a charge of -1 each).

Consider charge in an electron like a balance, with positively charged protons on one side and negatively charged electrons on the other. When you have the same number of each, there is equal amounts of positive and negative charge so the atom is neutral with a charge of zero.

For example, potassium has 19 protons, and 19 electrons. This means it has

19 positive charges and 19 negative charges. If you take away one electron, it now has 19 positive charges and 18 negative charges. So there is one more positive charge than negative, which means it is now an ion (a charged atom) with a charge of +1. If you take away two electrons the charge becomes +2... 4 electrons the charge becomes +4.