Tag: d- and f-block elements

Questions Related to d- and f-block elements

More number of oxidation states are exhibited by the actinoids than by lanthanoids. The main reason for this is:

chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

  1. greater metallic character of the lanthanoids than that of the corresponding actinoids.

  2. more active nature of the actinoids.

  3. more energy difference $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.

  4. lesser energy difference between $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.

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Correct Option: D
Explanation:

Actinoids display more oxidation states because of very small energy gap between 5f, 6d and 7s sub shells. Thus, the outermost electrons get easily excited to the  higher energy level giving variable oxidation state.

Hence,option D is correct.
 

Statement 1: Lanthanides have much less tendency to form complexes than actinides.
Statement 2: Compared to actinides, the lanthanides have relatively larger size of atoms and less nuclear charge.

chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

  1. Statement 1 is True, statement 2 is True, statement 2 is a correct explanation of statement 1.

  2. Statement 1 is True, statement 2 is True, statement 2 is not a correct explanation of statement 1.

  3. Statement 1 is true, Statement 2 is False.

  4. Statement 1 is False, Statement 2 is True.

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Correct Option: A
Explanation:

Because of higher effective nuclear charge and smaller size of atoms the actinides have higher charge density and because of that they have greater tendency to form complexes than the lanthanides.

The main reason for larger number of oxidation states exhibited by the actinoids than the corresponding lanthanoids, is:

chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

  1. the lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals

  2. more energy difference between 5f and 6d orbitals than between 4f and 5d orbitals

  3. greater reactive nature of the actinoids than the lanthanoids

  4. larger atomic size of actinoids than the lanthanoids

Show answer
Correct Option: A
Explanation:

Actinoids shows larger oxidation states due to poor shielding of both $4f$ and $5f$ orbital electrons as a result these orbital have almost similar energy and hence take part in bond formation. Also, there is very small energy between $5f, 6d$ and $7s$ subshells.

The number of oxidation states is exhibited by the actinoids more than by the lanthanide. The main reason for this is:

chemistry d- and f-block elements comparison of lanthanoids and actinoids actinoids the actinoids

  1. more energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals.

  2. the lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals.

  3. the greater metallic character of the lanthanoids than that of the corresponding actinoids.

  4. more active nature of the actinoids.

Show answer
Correct Option: B
Explanation:

Actinides show larger oxidation states due to poor shielding of both $4f$ and $5f$ orbital electrons, as a result, their orbitals have almost similar energy and hence take part in bond formation. Thus the energy gap between $5f, 6d$ and $7s$ become very small.

Which of the following ion will not form coloured aqueous solution?

chemistry d- and f-block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

  1. $Ni^{2+}$

  2. $Fe^{3+}$

  3. $Ti^{4+}$

  4. $Cu^{2+}$

Show answer
Correct Option: C
Explanation:
$ \displaystyle Ni^{2+}$ ion with $ \displaystyle 3d^8$ outer electronic configuration has two unpaired electrons. It will form a green coloured aqueous solution.

$ \displaystyle Fe^{3+}$ ion with $ \displaystyle 3d^5$ outer electronic configuration has five unpaired electrons. It will form yellow coloured aqueous solution.

$ \displaystyle Ti^{4+}$ ion will not form coloured aqueous solutionaas it does not contain unpaired electrons.
$ \displaystyle Ti^{4+}$ ion with $ \displaystyle 3d^0$ outer electronic configuration has zero unpaired electrons.


$ \displaystyle Cu^{2+}$ ion with $ \displaystyle 3d^9$ outer electronic configuration has one unpaired electron. It will form blue coloured aqueous solution.

Hence, option $C$ is correct.

Mass (g)
Empty crucible $22.01$
Crucible and copper oxide $42.01$
Crucible and copper product $(1^{st}mass)$ $39.87$
Crucible and copper product $(2^{nd}mass)$ $38.01$
Crucible and copper product $(3^{rd}mass)$ $38.01$

Copper ions can have multiple oxidative states. The data table above was obtained during a lab in which an unknown copper oxide was heated in a crucible.
From this data, what is the name of the unknown copper oxide?

chemistry d- and f-block elements some important compounds of transition elements general properties of transition metals the d-and f-block elements

  1. Copper(I) oxide.

  2. Copper (II) oxide.

  3. Copper (I) peroxide.

  4. Copper (II) peroxide.

Show answer
Correct Option: A
State True or False.
Fe$ _3$O$ _4$ is mixed oxide of FeO and Fe$ _2$O$ _3$. 
chemistry d- and f-block elements some important compounds of transition elements general properties of transition metals the d-and f-block elements

  1. True

  2. False

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Correct Option: A
Explanation:

Iron (II,III) oxide is the chemical compound with formula $Fe _3O _4$. It occurs in nature as the mineral magnetite. It is one of a number of iron oxides, the others being iron(II) oxide ($FeO$), which is rare, and iron(III) oxide ($Fe _2O _3$) also known as hematite. $Fe _3O _4$ contains both $Fe^{2+}$ and $Fe^{3+}$ ions and is sometimes formulated as FeO ∙ Fe2O3. 

The molecular formula of Rinmann's green is:

chemistry d- and f-block elements some important compounds of transition elements general properties of transition metals the d-and f-block elements

  1. $FeSO _{4}7H _{2}O$

  2. $CrCl _{3}$

  3. $NiSO _{4}7H _{2}O$

  4. $CoOZnO$

Show answer
Correct Option: D
Explanation:

Rinmanns green (CoO.ZnO) Cobalt green, is a translucent green pigment made by mixing cobalt(II) oxide and zinc oxide.