Which one is the wrong statement ?

Options

A. de-Broglie's wavelength is given by `lambda=(h)/(mv)`,
where
m = mass of the particle,
v = group velocity of the particle
B. The uncertainty principle is `Delta E xx Delta t ge h//4pi`
C. Half-filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement
D. The energy of 2s-orbital is less than the energy of 2 p-orbital in case of hydrogen like atoms

Answer

D

Explanation

(a) According to de-Broglie's equation,
Wavelength `(lambda)=(h)/(mv)`
where, h=Planck's constant.
Thus, statement (a) is correct.
(b) According to Heisenberg uncertainty principle , the uncertainties of position `(Delta x)` and momentum `(p=mDelta v)` are related as
`Deltax.Delta pge(h)/(4pi)`
or, `Deltax.mDeltav ge (h)/(4pi)`
`Deltax.m.Deltaa. Deltat ge(h)/(4 pi)`
[`(Delta v)/(Delta t)=Deltaa, a`=acceleration ]
or, `Deltax . F. Delta t ge (h)/(4pi) " " ` [`:' F=m. Delta a`]
or, `Delta E.Delta t ge (h)/(4pi) " " `[`:' DeltaE=F.Deltax, E`=energy]
Thus, statement (b) is correct.
(c) The half and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement. Thus statement (c) is correct.
(d) For a single electronic species like H, energy depends on value of n and does not depend on l. Hence energy of 2s-orbital and 2p-orbital is equal in case of hydrogen like species. Therefore, statement (d) is incorrect.