It is relatively easy to pull an electron away from a potassium atom (K, atomic number 19), but very difficult to remove a second one because ________.
A)of the repulsions occurring between electrons within the same shell
B)the electrons are so very small
C)of a much greater effective nuclear charge
D)very little energy remains after the first electron is removed

Question

Quizplus · Accepted Answer

The effective nuclear charge increases after the first electron is removed, making it more difficult to remove a second electron. This is because the remaining electrons now experience a greater attraction to the nucleus due to the reduced shielding effect of the removed electron.

It Is Relatively Easy to Pull an Electron Away from a Potassium