Amongst the elements with the following electronic configurations, which one of them may have the highest ionisation energy?

1. $\left[Ne\right]$ $3s^2$ $3p^3$

2. $\left[Ne\right]$ $3s^2$ $3p^2$

3. $\left[Ar\right]$ $3d^{10}$ $4s^2$ $4p^3$

4. $\left[Ne\right]$ $3s^2$ $3p^1$

Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species?

1.  F < Cl < O < S

2.  S < O < Cl < F

3.  O < S < F < Cl

4.  Cl < F < S < O

The ions O^2–, F^–, Na⁺, Mg²⁺, and Al³⁺ are isoelectronic. Their ionic radii show: 

In which following options of arrangement does not agree with the variation of the property indicated against it?

Choose the correct option

For the second period elements the correct increasing order of first ionisation enthalpy is:

1.  Li<Be<B<C<O<N<F<Ne

2.  Li<Be<B<C<N<O<F<Ne

3.  Li<B<Be<C<O<N<F<Ne

4.  Li<B<Be<C<N<O<F<Ne

Electronic configuration of chalcogens in their outermost orbit is:

1. s² p³

2. s² p⁴

3. s² p⁵

4. s² p⁶

If IUPAC name of an element is "unununium" then correct statement regarding element is:

The correct representation of the first ionization enthalpy for
Ca, Ba, S, Se, and Ar in increasing order, among the following, is:

1. Ba < Ca < Se < S < Ar

2. Ca < Ba < S < Se < Ar

3. Ca < S < Ba < Se < Ar

4. S < Se < Ca < Ba < Ar

The oxidation state and covalency of Al in [AlCl(H₂O)₅]²⁺ are respectively:

1. +3 and 3
2. +6 and 2 
3. +3 and 6
4. +2 and 2