Arrange elements according to ionization energy

Question

Hi, the question i need help is this:

Arrange the elements according to ionization energy level from highest to lowest

1. Kr, Br, Se, As, Ge, Ga, Ca, K
2. Na, Li, Rb, K

Answer 1

Ionization energy is the energy required to remove an electron from an atom to form an ion.

Ionization energy increases as you move across a row on the periodic table, i.e. Li < Be < B < C < N < O < F - so F has the highest ionization energy in that row

Ionization energy decreases as you move down a column on the period table, i.e. Be > Mg > Ca > Sr > Ba > Ra, Be has the highest ionization energy in that column.