Tag: d- and f-block elements

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

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

  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.
Reveal answer Fill a bubble to check yourself
D Correct answer
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.
 

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

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.

  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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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.
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. $Ni^{2+}$
  2. $Fe^{3+}$
  3. $Ti^{4+}$
  4. $Cu^{2+}$
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

  1. Copper(I) oxide.

  2. Copper (II) oxide.

  3. Copper (I) peroxide.

  4. Copper (II) peroxide.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Subtract the mass of the empty crucible (22.01 g) from the final copper product mass (38.01 g) to find the mass of copper, which is 16.00 g. Subtract the copper mass from the mass of the crucible and copper oxide (42.01 g - 22.01 g = 20.01 g total oxide minus copper gives oxygen mass), yielding 4.00 g of oxygen. Calculating the mole ratio of copper to oxygen gives 16.00/63.55 = 0.25 moles of Cu and 4.00/16.00 = 0.25 moles of O, resulting in a 1:1 empirical formula of CuO, which is copper(II) oxide.

Multiple choice chemistry d- and f-block elements some important compounds of transition elements general properties of transition metals the d-and f-block elements
State True or False.
Fe$ _3$O$ _4$ is mixed oxide of FeO and Fe$ _2$O$ _3$. 

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.