Test: General Properties of d-Block Elements - NEET MCQ

Since,1st transition series belongs to 3d orbital and 2nd transition series belongs to 4d-orbital. According to the given option, atomic number 39 to 48 (5s²4d^1-10) belongs to second transition series.

Mn²⁺/ Mn have - 1.18SRPvalue.

Ford-block elements, group number is equal to the number of electrons in (n - 1)d subshell + number of electrons in valence shell (nth shell).

[Kr]4d¹⁰5s⁰

Sc (3d¹ 4s²)has 631 kJ mol^-1 and Zn (3d¹⁰ 4s²) has 906 kJ mol^-1 

The element lying above Z = 42 has Z value 24, i.e. chromium. Hence, Cr configuration is [Ar]3d⁵4s¹

The correct answer is option C

Ce exist in the oxidation state other than +3 .

(a) B - Boron has +1 and +3 oxidation state.

(b) Al - Aluminium has +1,+2 and +3 oxidation state.

(c) Ce - Cerium has +3 and +4 oxidation state.

(d) Ga - Gallium has +1 and +3 oxidation state.

Cerium (Ce) have [Xe] 4f²6s² electronic configuration.

Fe (Z = 26) in + 3 oxidation state show Fe³⁺ ([Ar] 3d⁵) configuration. Ni(28) in +2 oxidation state show Ni²⁺([Ar]3d⁸) configuration.

Due to lanthanide contraction, Ag and Au have nearly same size.

Covalent radii tend to increase across a period from left to right and increase down a group in the periodic table. Elements that are close to each other in the periodic table are likely to have similar covalent radii.

Let's analyze each pair:

1. Nb (Niobium) and Ta (Tantalum):

   • Nb: Atomic number 41, Period 5, Group 5.
   • Ta: Atomic number 73, Period 6, Group 5.
   • These elements are in the same group and have similar atomic sizes. Therefore, their covalent radii are expected to be similar. (Correct)

2. Mo (Molybdenum) and W (Tungsten):

   • Mo: Atomic number 42, Period 5, Group 6.
   • W: Atomic number 74, Period 6, Group 6.
   • Similar reasoning as Nb and Ta, they are in the same group and likely have similar covalent radii. (Correct)

3. La (Lanthanum) and Lu (Lutetium):

   • La: Atomic number 57, Period 6, Group 3.
   • Lu: Atomic number 71, Period 6, Group 3.
   • These elements are in the same group but not directly next to each other in the periodic table. Their covalent radii may be similar but not as closely as within the same period or adjacent groups.

4. Sc (Scandium) and Y (Yttrium):

   • Sc: Atomic number 21, Period 4, Group 3.
   • Y: Atomic number 39, Period 5, Group 3.
   • These elements are in the same group but not in the same period. Their covalent radii may show some similarity due to being in the same group.

Based on the analysis:

• Option 1 (Nb and Ta) and Option 2 (Mo and W) are correct because these pairs are in the same group and are expected to have similar covalent radii.

Therefore, the correct answers are:

1. Nb and Ta

2. Mo and W

The correct answer is Option B.

Sc has the lowest density (3.1 g cm−3). It is the lightest transition element.

An element with pseudo noble gas configuration has 18 electrons in the highest energy level instead of 8.
Zn²⁺(28) = 3s², 3p⁶, 3d¹⁰
Ag⁺ (46) = 4s²4p⁶4d¹⁰

The correct answer is option A,D.
About two–thirds of all metals crystallize in closest-packed arrays with coordination numbers of 12. Metals that crystallize in an HCP structure include Cd, Co, Li, Mg, Na, and Zn, and metals that crystallize in a CCP structure include Ag, Al, Ca, Cu, Ni, Pb, and Pt.

Both Fe²⁺ and Co³⁺ have [Ar] 3d⁶ configuration while V²⁺ and Cr³⁺ have [Ar] 3d³.

Due to lanthanide contraction.

The high melting point of Cr metal is attributed to the involvement of greater number of electrons from (n - 1) d in addition to ns electrons in the interatomic metallic bonding.

(i) → (s), (ii) → (r), (iii) → (q), (iv) → (p)

Ni has 3d⁸4s² and Pt has 5d⁹6s¹.

Chromium has 6 unpaired electrons and hence, its spin value is - 3 or +3. Cr,

There are 6 unpaired electrons in chromium.

l = 2 means d-subshell. Zinc has 10 electrons ind-subshell in which 5 electrons are + 1/2 spin and 5 electrons are - 1/2.

Zn, Cd, Sc and La do not show variable valencies.

The correct answer is option C
In Electrolytic refining, the impure metal is made to act as an anode. A strip of the same metal in pure form is used as a cathode. 
They are put in a suitable electrolytic bath containing a soluble salt of the same metal. 
The more basic metal remains in the solution and the less basic ones go to the anode mud.
Copper is refined using an electrolytic method.
Impurities from the blister copper deposit as anode mud which contains antimony, selenium, tellurium, silver, gold, and platinum; recovery of these elements may meet the cost of refining.

Osmium has the electronic configuration 5de⁶s². As 5d and 6s are close in energy, all the 8 electron can participate in bonding. highest oxidation state of osmium is +8 due to its ability to expand their octet by using its all 8 electrons (2 from 6s and 6 from 5d).