Calculate the wavelength in Angstrom of the photon that is emitted when an electron in the Bohr orbit, n = 2 returns to the orbit, n = 1 in the hydrogen atom. The ionization potential of the ground state hydrogen atom is 2.17 $$\times$$ 10^-11 erg per atom.

The element with the highest first ionization potential is

There are ______ $$\pi$$ bonds in a nitrogen molecule.

____ hybrid orbitals of nitrogen atom are involved in the formation of ammonium ion.