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

5f series elements are known as_______

  1. Lanthanides

  2. Representative elements

  3. Transition elements

  4. Actinides
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Actinides are also called the 5f series.


 Filling up of the 5f orbitals after actinium (Z = 89) gives the 5f-inner transition series known as the actinoid series.

Option D is correct.

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

Actiniod contraction is more than lanthanold contraction because:

  1. energy of 4f and 5f orbitals are same

  2. 5f orbitals are more diffused as compared to 4f orbitals

  3. actinoids show greater range of oxidation states than lanthanoids

  4. actinoids are highly reactive
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$5f$ orbitals are bigger than $4f$ orbitals, in other words, $5f$ orbitals are more diffused thereby having the poor shielding effect. Hence have a more effective nuclear charge thereby having a small size. Hence actinide contraction is more than lanthanide contraction.

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

Assertion 


The degree of complex formation in actinides decreases in the order:

     $ \ M^{4+}>MO^{2+} _{2}> M^{3+}>MO^{+} _{2} $

Reason

Actinides form complexes with $\pi $ bonding ligands such as alkyl phosphines and thioethers.

  1. Both Assertion and Reason are correct and Reason is correct explanation for Assertion.

  2. Both Assertion and Reason are correct and Reason is not correct explanation for Assertion

  3. Both Assertion is correct but Reason incorrect.

  4. Both Assertion and Reason are incorrect
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The assertion regarding the order of complex formation is correct based on charge density. The reason is also factually correct regarding bonding, but it does not explain why the specific order of complex formation occurs, as that is primarily driven by the ionic charge and size (electrostatics).

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

Which of the following forms stable oxidation state?

  1. Ce+ , Yb+

  2. Eu + , Tb+

  3. Lu+, Gd

  4. Pr5+ ,Nd2+
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cerium (Ce) and Ytterbium (Yb) can exhibit stable +4 and +2 oxidation states respectively due to stable electronic configurations (f0 and f14), making Ce+ and Yb+ (or their related stable ions) notable in lanthanide/actinide chemistry contexts.

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

Actinoids belongs to following type of elements:

  1. s -block element

  2. d -block element

  3. f -block element

  4. p -block element
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The two rows that are generally placed underneath the main Periodic Table are called the lanthanide series and the actinide series.

These two rows are produced when electrons are being added to f orbitals.

Therefore, this block of elements are referred to as the "f block".

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

Which of the following elements is placed just after actinide series?

  1. Rutherfordium

  2. Unnilpentium

  3. Unnilquadium

  4. Ununbium
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

Actinide series starts with actinium (Z=89) and contains fourteen elements from thorium (Z=90) to lawrencium (Z=103). This is followed by Rutherfordium (Z=104). There Rutherfordium (Z=104) also known as Unnilquadium.

Hence, both a and c are the correct option.

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

The bonds generally formin compounds of Actinoids are:

  1. convalent

  2. ionic

  3. coordinate covalent

  4. metallic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Actinoids are highly electropositive elements, and their compounds are predominantly ionic in nature due to the large size of the ions and the relatively low electronegativity of the metals.

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

In the general electronic configuration,
$(n-2)f^{1-14} (n-1)d^{01} ns^2$ (where n = 7) the configuration will be of:

  1. lanthenides

  2. actinides

  3. transition elements

  4. none
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

General electronic configuration is given:
$(n -2) f^{1 -14} (n -1) d^{0 1} ns^2 ,where ( n =7 )$
$5f^{1 -14} 6d^{0 1 }ns^2$
The seventh period $(n=7)$ is similar to the sixth period with the successive filling up of the 7s, 5f, 6d and 7p orbitals and includes most of the man-made radioactive elements. This period will end at the element with atomic number 118 which would belong to the noble gas family. Filling up of the 5f orbitals after actinium $(Z=89)$ gives the 5f-inner transition series known as the Actinoid Series.