1. which type of elements will form cations, metals or non-metals? explain why.

2. list the elements that are an exception to the rule and explain why.

Explanation:

1) Cations are also called Cathode ions. They are positively charged ions. They are formed when an atom loses electron.

The tendency of an atom to lose electron decreases across the period of the periodic table. This explains why Lithium(metal) in group 1 prefers to lose an electon and attain stability where as Fluorine(non metal) accepts electron though they but belong to the same period 1 on the periodic table.

Metals form cations and not non-metals

2) The exceptions include:

Hydrogen: though it belong to group 1, yet hydrogen is not a metal but a gas at room temperature. Hydrogen has half filled orbital. Hydrogen bonds covalently.