Why does the metal ions that form their ions most easily,will accept the electrons with greatest difficulty?

When an electron is added to a metal element, energy is needed to gain that electron (endothermic reaction). Metals have a less likely chance to gain electrons because it is easier to lose their valance electrons and form cations. It is easier to lose their valence electrons because metals' nulcleis do not have a strong pull on their valence electrons. Thus, metals are known to have lower electron affinities. Metals easily lose electrons to attain stable octet electron configuration.