Which of the following two ions have the same number of unpaired electrons ?
(1) Mn3+ (2) Fe3+ (3) Cr3+ (4) Co3+
(2) and (3)
(3) and (4)
(1) and (2)
(1) and (4)
The lanthanoid contraction is responsible for the fact that
Zn and Y have about same radius
Zr and Nb have similar oxidation states
Zr and Hf have about the same radius
Zr and Zn have the same oxidation state
The equivalent weight of MnSO4, is equal to its molecular weight when it is converted to
Mn2O3
MnO2
MnO
MnO
The mineral from which potassium permanganate is manufactured
manganite, Mn2O3.H2O
pyrolusite, MnO2
Both (a) and (b)
None of the above
Which one of the following transition metal ion is coloured?
Cu+
Zn2+
Sc3+
V4+
D.
V4+
Among the given options, V4+ is coloured.
The electronic configuration of V4+ is [Ar]3d1 4s0. It has one unpaired electron in its d-subshell. On exposure to visible light, the excitation of unpaired d-electrons takes place from lower to higher energy d-sublevels. The d-d excitation during complex formation permits the absorbance of required wavelength and rest light is transmitted out. Thus, transition metals or metal ions having unpaired d-electrons appears coloured.
The aqueous ferrous ion is green, ferric ion is pale yellow. The aqueous chromic ion is green, hence the colour of chromate ion must be
orange
colourless
yellow
red
belongs to IIIB group of the Periodic.When it loses one α -particle, the new element will belong to the group.
I B
V B
I A
III B
Which set of elements have nearly the same atomic radii ?
F, Cl, Br, I
Na, K, Rb, Cs
Fe, Co, Ni, Cu
Li, Be, B, C