Properties of the elements are given below. Where would you locate the following elements in the periodic table?
$(a)$ An element which is an inert gas with atomic number $2$.
$(b)$ An element whose thin oxide layer is used to make other elements corrosion resistant by the process of 'anodising'.

$(i)$ The elements of the second period along with their atomic numbers in parentheses are given below: $B(5)$,$Be(4)$,$O(8)$,$N(7)$,$Li(3)$,$C(6)$,$F(9)$.
$(a)$ Arrange them in the same order as they appear in the periodic table.
$(b)$ Which element has the largest and smallest atom?
$(ii)$ Why does the atomic radius change as we move from left to right in a period?

Which of the following elements will form an acidic oxide?

The order of decreasing atomic size is:

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

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