Probability density is given by

Statement 1 : The plots of probability density and radial probability function versus distance r from the nucleus for any particular orbital are not identical, Statement 2 : Probability density is psi^(2) whereas radial probability function represents probability of finding the electron in a shell of thickness dr.

For the probability distribution given by The standard deviation (sigma) is

For the probability distribution given by the standard deviation (sigma) is

Probability density curve for 3s orbital

Statement -I : Probability density of electron is zero at nucleus for all p & d orbitals. Statement -II : Probability density of electron at the nucleus depends upon azimuthal quantum number only.