Give two reasons to explain how the metallic character of elements varies: $(a)$ in a group,$(b)$ in a period.

$(a)$ Electropositive nature of the element$(s)$ increases down the group and decreases across the period.
$(b)$ Electronegativity of the element decreases down the group and increases across the period.
$(c)$ Atomic size increases down the group and decreases across a period (left to right).
$(d)$ Metallic character increases down the group and decreases across a period.
On the basis of the above trends of the Periodic Table,answer the following about the elements with atomic numbers $3$ to $9$:
$(a)$ Name the most electropositive element among them.
$(b)$ Name the most electronegative element.
$(c)$ Name the element with the smallest atomic size.
$(d)$ Name the element which is a metalloid.
$(e)$ Name the element which shows maximum valency.

Which of the following sets of elements is written in the order of their increasing metallic character?

It was assumed by Newlands that only :

Which of the following gives the correct increasing order of the atomic radii of $O$,$F$ and $N$?

Write true or false for the statement: Electronic configuration of hydrogen resembles that of alkaline earth metals.