1. There are 8 electrons. Elements that end with 2p orbitals are in the 2nd period (aka row) of the periodic table. Elements that have 4 electrons in 2p are in the 16th group (aka column) (column 16 may also be referred to as 6A) of the periodic table. So looking at row 2, column 16, we can see that the first diagram is of O, Oxygen.
2. 8 electrons. This is the same diagram as the one above.
3. 13 electrons. Elements ending with 3p are in period 3. Elements with 1 valence electron in a p orbital are in group 13 (aka group 3A).
4. 7 electrons. We already know 2p is period 2. 3 valence electrons in a p orbital means that it is in group 15/group 5A.
I did not write the answers for #3 and 4 but they can be easily found on a periodic table with the info I gave.
I would say it is a chemical change because after a while, the nails start to rust. Now they only rust after about a week though. But rust is a chemical change.
