Oxidation States of Lanthanides

Q.

How do we know the valency of a polyatomic ion? Such as hydroxide and many others.

Q.

In which of the following elements +1 oxidation state is more stable than +3 oxidation state?

1. Ga

2. Al

3. Tl

4. In

Q.

Question 16.1

Explain the following in terms of gain or loss of oxygen with two examples each:

Oxidation.

Q.

The element showing most stable +8 oxidation state in its compound is

1. Os
2. Ni
3. Re
4. Ru

Q. The reason for the stability of Gd${}^3+$ ion is

1. 4 f sub shell- completely filled
2. Possesses the general electronic configuration of noble gases
3. 4 f sub shell- half filled
4. 4 f sub shell empty

Q. In aqueous solution, Eu${}^2+$ ion acts as a/an

1. oxidizing agent
2. reducing agent
3. either a) or b)
4. none of these.

Q. The compound formed in the borax-bead test of $C{u}^{2+}$ ion in oxidizing flame is:

1. $Cu{\left(B{O}_2\right)}_2$
2. $Cu$
3. $CuB{O}_2$
4. none of these

Q. In context of the lanthanoids, which of the following statements is not correct?

1. All the members exhibit +3 oxidation state.
2. Because of similar properties the separation of lanthanoids is not easy.
3. Availability of 4f electrons results in the formation of compounds in +4 state for all the members of the series.
4. There is a gradual decrease in the radii of the members with increasing atomic number in the series.

Q. Choose incorrect option for 3-d transition series:-

1. Density increases from Ti to Cu
2. enthalpy of atomization is lowest for manganese
3. Cr²⁺ is a strong reducing agent
4. first ionization enthalpy is highest for zinc

Q.

1. True
2. False

Q. Ozone on reacting with hydrogen sulphide gives a compound whose central atom has ___________oxidation state.