Question

Hydride gap' is referred to which region of the periodic table?

• A. Group 3,4,and 5
• B. Group 5,6 and 7
• C. Group 7,8 and 9
• D. Group 3,5 and 7

Answer 1

The correct option is C

Group 7,8 and 9

The explanation for the correct option:-

Option (C): Groups 7,8 and 9

• The group 7,8 9 elements do not form hydrides.
• This is because when they are reacted with hydrogen, hydrogen donates its valence electron to the metals, hence hydride is not formed.
• The elements of this group have a low affinity for hydrogen, and hence they do not gorm hydride.
• Some examples of such elements are Iron(Fe), Cobalt(Co), and Manganese(Mn).
• Therefore, this region is called the hydride gap.

The explanation for the incorrect option:-

Option (A): Group 3,4,and 5

• The d-block and the f-block elements form hydride when heated with hydrogen at high temperatures.
• Thus these groups forms hydride and these hydrides are non-stoichiometric.
• Examples are ${\mathrm{ScH}}_3,{\mathrm{TiH}}_2,\mathrm{VH}$.
• Hence it is the incorrect option.

Option (B): Group 5,6 and 7

• In group 6 there is only one element that forms hydride, and that element is Chromium(Cr), it forms $\mathrm{CrH}$.
• Thus this region cannot be called the hydride gap.
• Hence it is the incorrect option.

Option (D): Groups 3,5 and 7

• Group 3 and 5 elements can form hydride at high temperatures.
• As the electronegativity of these elements and that of hydrogen are very similar.
• Thus this region cannot be the hydride gap.
• Examples are ${\mathrm{ScH}}_3,\mathrm{VH},{\mathrm{H}}_2\mathrm{Mn}$.
• Hence, incorrect option.

Therefore, the Hydride gap' is referred to as option (C): Group 7, 8 and 9 regions of the periodic table.