Question

2) (a) Name the three quantum numbers that define the wavefunction for a hydrogenic 1 electron) orbital, and briefly state what each number defines. (b) According to the rules for quantum numbers, state which orbitals from the following list are not allowed and explain what rule is being violated: 1s, 1p, 3p, 3f, 4d, an orbital with 2 and mi -2, an orbital with0 and mi+1

Answer 1

Principal quantum number : This defines the orbital energy. Represenation is shown by n .

n = 1 indicates lowest energy level

Angular moment quantum number : Its indicated by l . It tells about shape of orbitals. l has values from 0 to n-1

Magentic quantum number : Inidcated by ml . It tells about how each orbital spilts under magnetic field. ml will have values from - l to +l

b) Based on rules , 1p orbital is wrong since 1p means n = 1 , so l can have only l = 0 value. l=0 indicates "s"

Hence we can have 1s not 1p

3f also not possible since n = 3 , l can have maximum value of n-1= 3-1 = 2 which indicates d

( l = 0 means s , l = 1 means p , l = 2 means d , l = 3 means f)

when l = 0 we cannot have ml = +1 , since ( ml can have values from = - l to + l)