Ap chemistry help?????????????

Question

hey there. can someone explain this to me (as simple as possible)? its in my chemistry ap prep book, but i dont understand it.

heres what it says:

The attraction an electron experiences is due to effective nuclear charge, which is a result of positive nuclear charge interacting with the negative electrons.

Electrons between the nucleus and the electron under consideration interfere with, or shield, that electron from the full nuclear charge. this shielding lessens the nuclear charge. within a period, the shielding is nearly constant; however, the effective nuclear charge will increase with an increasing # of proteons. within the same family, as the atomic number increases, so does the shielding, resulting in a relatively constant effective nuclear charge.

sorry if this is kinda text-heavy. thanks a bunch in advance.

Answer 1

As one goes from H to He, the electrons are 1s1 and 1s2. From Li to Ne, the electrons run from 2s1 to 2s22p6. But the closed shell of 1s2 shields the electrons in upper levels from the full force of all the protons. For example, the 2s1 electron of Li is attracted by only one proton in the nucleus. The 2s2 electrons of Be are attracted by only two protons and are shielded from the rest.

Answer 2

if you have electrons between the nucleus and other electrons, the electrons closer to the nucleus will shield the electrons that are further away from the nucleus from 'feeling' the full pulling power of the protons in the nucleus.