Which two factors affect the strength of
a metallic bond?

Number of protons and number of valance electrons.

Explanation:

There are three factors which determine metallic bond strength. greater the no of protons, greater will be attraction between nucleus and valance shell electrons and stronger will be metallic bond. greater no of valance electron, greater will be attractions between nucleus and electrons and stronger will be bond.

argon

For example, the K+ ion is isoelectronic with argon. Potassium has 19 electrons and 1 is in the outermost shell: a valence electron. If potassium is ionized and becomes a +1 cation, this is to say that it lost its single valence electron. This is favorable, because it gives potassium a noble gas configuration