Which of the following set of properties generally decreases along a period?

Which elements in groups $1$ to $17$ differ in many respects from the other elements of their respective groups?

Which of the following is the correct order of $I.E.$ (Ionization Energy)?

The ionisation enthalpies of elements of the second period are given below: Ionisation enthalpy / $kcal \, mol^{-1}$: $520, 899, 801, 1086, 1402, 1314, 1681, 2080$. Match the correct enthalpy with the elements and complete the graph given in Fig. Also,write the symbols of the elements with their atomic numbers.

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

Given below are two statements $:$
Statement $(I) :$ The radii of isoelectronic species increase in the order $Mg^{2+} < Na^{+} < F^{-} < O^{2-}$.
Statement $(II) :$ The magnitude of electron gain enthalpy of halogens decreases in the order $Cl > F > Br > I$.
In the light of the above statements,choose the most appropriate answer from the options given below $:$