Which one of the following has the regular tetrahedral structure?
(Atomic nos : B = 5, S = 16, Ni = 28, Xe = 54)

The maximum number of 90° angles between bond pair of electrons is observed in

As the temperature is raised from 20°C to 40°C, the average kinetic energy of neon atoms changes by a factor of which of the following?

In Van der Waals equation of state of the gas law, the constant ‘b’ is a measure of