Question

Which Element Has Highest IE in the Periodic Table?

Answer 1

1. The amount of energy required to remove the electron from the outermost shell is called ionization energy.
2. It can be measured in terms of electron volts.
3. A general trend is followed in the periodic table as we move left to right in the periodic table the ionization energy increases.
4. But as we move down the group, the decrease in ionization energy is observed.
5. The ionization energy decreases down the group because, new shells are added which tend to decrease the nuclear charge, and hence the electrons are removed easily.
6. In the case of periods as we move along the period the nuclear charge increases which tightly bounds the electrons and so it is difficult to remove the electron.
7. The last element in the period is Helium.
8. The atomic number of Helium is $2$, and the electrons are closer to the nucleus and hence higher is the ionization energy.