In a transition series, with increase in atomic-number, the paramagnetism
increases gradually
decreases gradually
first increases to a maximum and then decreases
first decreases to a minimum and then increases
C.
first increases to a maximum and then decreases
The paramagnetism of transition elements of a given series increases on moving left to rght in a period and attain a maximum value and after that, it goes on decreasing towards the end of period. This is due to the fact that the magnetic moment or paramagnetism is directly related to the number of half-filled d-orbitals. In the beginning, the number of unpaired electrons in d-orb1tals increases till the middle of the period (d1 to d5). After this, the pairing of electrons occurs in d-orbitals (d6 to d10).
Thus, in a given transition senes, with increases in atomic-number, the paramagnetism first increases
to a maximum and then decreases.
The bivalent metal ion having maximum paramagnetic behaviour among the first transition series elements is
Mn2+
Cu2+
Sc2+
Cu+
Mn2+ compounds are more stable than Fe2+ compounds towards oxidation to their +3 state, because
Mn2+ is more stable with high 3rd ionisation energy
Mn2+ is bigger in size
Mn2+ has completely filled d-orbital
Mn2+ does not exist
The correct statement is
The earlier members of lanthanoid series resemble calcium in their chemical properties.
The extent of actinoid contraction is almost the same as lanthanoid contraction.
In general, lanthanoid and actinoids do not show variable oxidation states.
Ce4+ in aqueous solution is not known.
When a brown compound of Mn (A) is treated with HCl, it gives a gas (B). The gas (B) taken in excess reacts with NH3 to give; an explosive compound (C). The compounds A, B and C respectively are
A - MnO2; B - Cl2; C - NCl3
A - MnO; B - Cl2; C - NH4Cl
A - Mn3O4; B - Cl2; C - NCl3
A - MnO3; B - Cl2; C - NCl2
Which of the following is a negatively charged bidentate ligand?
Cyano
Ethylene diamine
Acetato
Dimethyl glyoximato
The electronic configuration of Gd2+ is (atomic number of Gd is 64).
[Xe]4f8
[Xe]4f7
[Xe]4f7 5d16s2
[Xe]4f7 5d1