Which of the following pairs shows opposite trends when moving from left to right in a period and from top to bottom in a group?

Which of the following order$(s)$ is/are correct?
$(1) Li < Be < B < C$ $(IE_1)$
$(2) Li < Na < K < Rb < Cs$ (Reducing power in gaseous state)
$(3) Li^{+} < Na^{+} < K^{+} < Rb^{+} < Cs^{+}$ (Ionic mobility in aqueous solution)
$(4) S > Se > Te > O$ $(EA)$

Which element from the following exhibits a diagonal relationship with $Mg$?

Identify the correct statements from the following.
$(i)$ In the periodic table,about $78 \%$ of elements are metals.
$(ii)$ In a group,the metallic character decreases from top to bottom and in a period the nonmetallic character decreases from left to right.
$(iii)$ The element $Ho$ belongs to $f-$block.

The atomic numbers of elements $A, B, C$ and $D$ are $Z-1, Z, Z+1$ and $Z+2$,respectively. If $B$ is a noble gas,choose the correct statements from the following:
$(1)$ $A$ has high electron affinity
$(2)$ $C$ exists in $+2$ oxidation state
$(3)$ $D$ is an alkaline earth metal

Maximum enthalpy change is associated with which of the following reactions?