Question

plz answer question no. 4

Answer 1

Hydrogen is a very small atom. So the proton is very close to the electron.  So the electron is attracted to the proton. But in Sodium or other metals, the outermost orbit electrons are quite far away from the nucleus. So they are more electropositive and are more ready to lose electrons. The inner electrons act as shields to hide the nucleus from the outermost electron.

Thus metals lose electrons to form ions. So they form ionic bonds. Hydrogen forms more of covalent bonds. Hydrogen shares electrons more than metals, rather than losing them.

Answer 2

because hydrogen is more smaller than sodium