Hydogen can be placed in group 7. Explain.

Electronic configuration: Hydrogen like alkali metals has one electron in it's valence shell. Electropositive character: Hydrogen like alkali metals is electropositive because it can lose one electron readily to form hydrogen ion (H+).

so hydrogen can either loss or gain electron

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.