Consider the hydrogen atom to be a proton embedded in a cavity of radius a₀ (Bohr radius) whose charge is neutralised by the addition of an electron to the cavity in vacuum, infinitely slowly. Estimate the average total energy of an electron in it's ground state in a hydrogen atom as the work done in the above neutralisation process. Also, if the magnitude of the average kinetic energy is half the magnitude of the average potential energy, find the average potential energy.

Which of the following has the maximum number of unpaired electrons?

When N₂, the N-N bond distance _____ and when O₂ goes to $$O_2^+$$ the O-O bond distance ___.

The number and type of bonds between two carbon atoms in CaC₂ are: