Very briefly explain the main horizontal and vertical features of the Periodic Table in terms of the electronic structure and relevant quantum numbers?

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Am I being asked to state for instance in the case of Halogens that as we progress down the column the quantum electronic configuration gets more complex i.e the quantum numbers get higher and they only need one electron to fill the p-subshell? And how the valance electrons determine reactivity?

1 answer

I think the answer is yes for the electronic structure but I don't know what they want the "relevant" quantum numbers.