Na or Al Second Ionization Energy

[Lily Cornett 1H]

Hi! I was a little confused on the midterm question that asked about which element had the smaller second ionization energy, Na or Al? How does it differ from the first ionization energy?

[806144197]

Ionization energy is the energy needed to remove an electron from an atom. Once an electron is removed, the energy need to remove another, second electron is called the second ionization energy. Sodium has the configuration 1s2 2s2 2p6 3s1 while aluminum has the configuration 1s2 2s2 2p6 3s2 3p1. Sodium has one electron with an energy level (n) of 3 while Al has 3 electrons in its outer shell of n=3. After 1 electron is removed from Na, the next available electron is in the second shell. The second shell is much closer to the positive nucleus of the atom which means they experience stronger attraction forces. This means n=2 electrons require more energy to remove due to attractive forces between the nucleus and the electrons. Al has both of the electrons removed from the 3rd shell which means the second one requires less energy to remove because it is further from the nucleus.

[litty606]

Hi! The first ionization energy is the energy required to remove the first electron from an atom and the second ionization energy is the energy required to remove the second electron. So in the case of Na and Al:

First: Al-> Al+ +1 e-
Second: Al+ -> Al 2+ e-

First: Na -> Na+ + 1 e-
Second: Na -> Na 2+ + 1 e-

Since the ionization energy is greater from left to right and down up, on the chart, Al would have a lower ionization energy as the number of electrons it has is 11 in comparison to Na which would be 17. FYI looking at the periodic table helps alot in this process.