Which of the following is the outermost shell for elements of period $2$?

Name the element which has:
$(a)$ the electronic configuration $2, 8, 1$.
$(b)$ a total of two shells,with $4$ electrons in the valence shell.
$(c)$ a total of three shells,with $3$ electrons in the valence shell.
$(d)$ one shell which is completely filled with electrons.
$(e)$ twice as many electrons in the second shell as in the first shell.

Which of the following is the outermost shell for elements of period $2$?

Why do you think the noble gases are placed in a separate group?

Three elements $B, Si$ and $Ge$ are:

Which of the given elements $A$,$B$,$C$,$D$ and $E$ with atomic numbers $2$,$3$,$7$,$10$ and $30$ respectively belong to the same period?