What is the electronic configuration of sulphur?

$(a)$ Name the element with atomic number $17$.
$(b)$ To which period does it belong?
$(c)$ To which group does it belong?
$(d)$ Write its electronic configuration.

Which element has
$(a)$ a total of three shells,with four electrons in its valence shell?
$(b)$ a total of two shells,with three electrons in its valence shell?
$(c)$ twice as many electrons in its second shell as in its first shell?

The element with atomic number $14$ is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

$Na, Mg, Al, Si, P, S, Cl$ and $Ar$ are the elements of the third period.
$(a)$ Which one of them is an inert gas? Why?
$(b)$ Which one of them has a valency of $4$? What kind of bond does it form: ionic or covalent?
$(c)$ Which of them are electropositive? Pick any two.

How many vertical columns are there in the modern periodic table and what are they called?