Question

The value of ground state energy of hydrogen atom is negative

Answer 1

the ground state energy of Hydrogen atom = energy of electron in the principal quantum number n = 1..

E = - 13.6 eV

It is negative because it is the electrostatic binding energy between positively charged proton and negatively charged electron. The binding potential energy is negative always.

Also it means that we need to supply an energy of +13.6 eV to break the electron from the system.