Question

please someone explain this I dont get it at all. how do we know that the 4th electron came from 2p because it's at 4th ionisation? why is it talking about 3s?? how do overall know that aluminium is in group 3 from the table??? thanks​

Answer 1

When you look at a table of ionization, you will see that certain groups, or columns, on the periodic table will either lose or gain a certain number of electrons. We can also see that aluminum is in the third column, hence it is in group 3