If element a has an ionization energy of 419 KJ/mo1 and Element b has an ionization of 1000 KJ/mo1. which element is more likely to lose electrons? Why?

element a is more likely to lose an electron.

Explanation:

ionization energy of an atom is the minimum amount of energy required to remove an valence electron from the atom. ionization energy decreases down the group as effective nuclear charge and increases along the group as effective nuclear charge increases.

if the ionization energy is high it becomes more difficult to remove an electron. so element has less ionization energy compared to b so it will more likely lose an electron.