Question

Which of the following statement is wrong?
A. In the lanthanide series the electrons occupy `4f`-orbitals in preference to `5d` the and `6p`-orbitals.
B. Zero group was not present in the periodic table when Mendeleev presented it.
C. Law of octave was presented by Newland.
D. Cuprous compounds are coloured while cupric compounds are colourless.

Answer 1

Correct Answer - D
(d) Statement (d) is wrong.
`Cu(Z = 29), 3rd^(10), 4s^(1)`
`Cu^(o+)` (cuprous) `= 3d^(10) 4s^(0)`
`Cu^(2+)` (cupric) `= 3d^(9) 4s^(0)` (one unpaired electron and hence is coloured).