Question

In some forms of the periodic table, hydrogen is placed in Group I; in others, it is placed in Group VII. Give arguments in favor of each location.

Short answer

The placement of the H-atom is justified in both positions as H-atom acts as a donor (proton) like the alkali metals and as an acceptor (hydride) like the group 7 halogens.

Step-by-step solution

Periodic table.

The table is formed for arranging the elements in a sequence. As observed, the metals, metalloids, and non-metals are sequentially placed in the table.

The H-atom in Group 1.

The electronic configuration of the H-atom is $1s^1$.

As there is only one electron in the outermost shell, the hydrogen atom can achieve a noble gas configuration by donating one electron like alkali metals.

$$\begin{gathered} \text{H}\underset{}{\to }{\text{H}}^{\text{+}}+e^{-} \\ \text{Li}\underset{}{\to }{\text{Li}}^{\text{+}}+e^{-} \\ \text{Na}\underset{}{\to }{\text{Na}}^{\text{+}}+e^{-} \end{gathered}$$

The H-atom in Group 7.

The hydrogen atom can also achieve a noble gas configuration by accepting 1 electron like halogens (non-metals).

$$\begin{gathered} \text{H}+e^{-}\underset{}{\to }{\text{H}}^{-} \\ \text{F}+e^{-}\underset{}{\to }{\text{F}}^{-} \\ \text{Cl}+e^{-}\underset{}{\to }{\text{Cl}}^{-} \end{gathered}$$