Mention any two trends exhibited by elements when we go from left to right across the period of the periodic table.

Write true or false for the statement: It was assumed by Newlands that only $63$ elements existed in nature and no more elements would be discovered in the future.

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

The position of some elements $A, B, C, D, E, F$ and $G$ in the Modern Periodic Table is given as under:

Group $\to$	$16$	$17$	$18$
Period $1$			$A$
Period $2$	$B$	$C$	$D$
Period $3$	$E$	$F$	$G$

$(a)$ In which group are inert elements placed?
$(b)$ What type of ions would $B, C, E,$ and $F$ form?
$(c)$ Which element would have chemical properties similar to $C$?
$(d)$ How many shells would $A$ have?
$(e)$ What is the similarity between $A$ and $D$?
$(f)$ Identify the most abundant element in the earth's crust.

Explain the basic character of oxides of elements down the group and across the period.

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order? Give reason.