Among the elements of the main group, the general trend in the first ionization energy moving across a period is not followed between group 2 and group 13. which best explains these exceptions?
the ionization energy decreases because the full s orbital shields the electron entering the p orbital.
the ionization energy increases because the full s orbital shields the electron entering the p orbital.
the ionization energy decreases because the stability of the half-full p subshell is increased.
the ionization energy increases because the stability of the half-full p subshell is increased.

Idid a lab for chemistry where we put nails in a copper (ii) chloride solution. 1. why did the reaction stop? which reactant was used up? how do you know? 2. describe what was happening to the atoms of iron and copper during the reaction. what is this type of reaction called? 3. what would happen to the ratio of copper to iron if you had placed more nails in the beaker? if you had let the reaction go for less time? 4. what is the accepted ratio of copper atoms to iron atoms in this reaction? account for differences between your experimental value and the accepted value. write the balanced equation for the reaction.