Due to the screening effect, the 3s electrons of magnesium (Mg) feel an effective nuclear charge (Zeff) of:

Question

1. +1
2. +2
3. −2
4. +12
5. +4

Answer 1

nuclear charge = +12
1s, 2s, & 2p electrons = 10
+12-10 = 2 for the effective nuclear charge on the two 3s outside electrons

Answer 2

I couldn’t understand please explain this again

Answer 3

nuclear charge = +2
Mg has a nuclear charge of +2.