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'.

Given below are some elements of the modern periodic table. Atomic numbers of the elements are given in the parentheses: $A(4), B(9), C(14), D(19), E(20)$.
$(a)$ Select the element that has one electron in the outermost shell. Also,write the electronic configuration of this element.
$(b)$ Which two elements amongst these belong to the same group? Give reason for your answer.
$(c)$ Which two elements amongst these belong to the same period? Which one of the two has a bigger atomic radius?

$(a)$ In this ladder (Figure),symbols of elements are jumbled up. Rearrange these symbols of elements in the increasing order of their atomic number in the Periodic Table.
$(b)$ Arrange them in the order of their group also.

Which one of the following depicts the correct representation of atomic radius $(r)$ of an atom?

The electronic configurations of $4$ elements $A, B, C,$ and $D$ are as follows:
$A: 2, 1$
$B: 2, 2$
$C: 2, 8, 2$
$D: 2$
$(a)$ Which of these elements belong to the same group? Name them.
$(b)$ Which of these elements belong to the same period? Name them.
$(c)$ Which of these elements is inert? Name it.

Study the following table in which positions of six elements $A, B, C, D, E$ and $F$ are shown as they are in the modern periodic table:

Group $\to$	$1$	$2$	$13$	$14$	$15$	$16$	$17$	$18$
Period $2$	$A$	-	-	-	$B$	-	-	$C$
Period $3$	-	-	$D$	$E$	-	-	-	$F$

On the basis of the above table,answer the following questions:
$(i)$ Name the element which forms only covalent compounds.
$(ii)$ Name the element which is a metal with valency three.
$(iii)$ Name the element which is a non-metal with valency three.
$(iv)$ Out of $D$ and $E$,which is bigger in size and why?
$(v)$ Write the common name for the family to which the elements $C$ and $F$ belong.