Question

Lithium is the first element in group one and beryllium is the first in group 2. Which one is high ionization energy?

Answer 1

Answer:

beryllium

Explanation:

the ionization energy seems to decrease from right to left and from top to bottom in periodic table

Answer 2

Beryllium has higher ionization energy.

Beryllium has a smaller atomic size as compared to lithium, so the effect of greater positive nuclear charge on the valence electrons(due to higher atomic no. in Be as compared to Li) is more in Be as compared to Li, more amount of energy is hence needed to overcome this greater positive nuclear charge to remove the most loosely bound electron/s in Be as compared to Li. Hence, Be has greater ionization energy.