Place the elements in each set in order of increasing ionization energy.
a. O, N, C
b. S, P, Cl
c. As, P, N
d. Al, Si, P

We are given O, N, C elements. We have to arrange them in increasing ionization energy.

As we know ionization energy increases from top to bottom and from left to right in the Periodic Table.

Therefore, From O, N, C, the increasing order of ionization energy would be $\mathrm{C}<\mathrm{N}<\mathrm{O}$

We are given S, P, Cl elements. We have to arrange them in increasing ionization energy.

As we know ionization energy increases from top to bottom and from left to right in the Periodic Table.

Therefore, From S, P, Cl, the increasing order of ionization energy would be $\mathrm{P}<\mathrm{S}<\mathrm{Cl}$

We are given As, P, Cl elements. We have to arrange them in increasing ionization energy.

As we know ionization energy increases from top to bottom and from left to right in the Periodic Table.

Therefore, From As, P, N, the increasing order of ionization energy would be$\mathrm{As}<\mathrm{P}<\mathrm{N}$

We are given Al, Si, P elements. We have to arrange them in increasing ionization energy.

As we know ionization energy increases from top to bottom and from left to right in the Periodic Table.

Therefore, From Al, Si, P, the increasing order of ionization energy would be $\mathrm{Al}<\mathrm{Si}<\mathrm{P}$