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d- and f-Block Elements · Question 4

JEE Main 2026 (Online) 6th April Evening ShiftMCQMedium📈 Topic in 13% papers+4−1
1

The correct order of first ( iH1) and second ( iH2) ionisation enthalpy values of Cr and Mn are : Choose the correct answer from the options given below :

  1. A and B only
  2. B and C only
  3. A and D only
  4. C and D only

Answer

(2) B and C only

Solution

Cr: [Ar]3d54s1; Mn: [Ar]3d54s2

iH1: Mn loses an electron from a filled 4s subshell with a stable 3d5 core ⇒ Mn (717 kJ mol-1) > Cr (653 kJ mol-1) ⇒ C is correct

iH2: Cr+ is 3d5 (half-filled, stable) while Mn+ is 3d54s1 ⇒ Cr (1592 kJ mol-1) > Mn (1509 kJ mol-1) ⇒ B is correct

∴ B and C only

Answer: (2)

JEE Main 2026 (Online) 6th April Evening Shift

Keep practising — d- and f-Block Elements

2

Which of the following is NOT a physical or chemical characteristics of interstitial compounds?

  1. They have high melting points, higher than those of pure metals.
  2. They are very soft and ionic in nature.
  3. They retain metallic conductivity.
  4. They are chemically inert and usually non-stoichiometric.
JEE Main 2026 (Online) 5th April Morning Shift
3

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are correct
  2. Both Statement I and Statement II are incorrect
  3. Statement I is correct but Statement II is incorrect
  4. Statement I is incorrect but Statement II is correct
JEE Main 2026 (Online) 5th April Evening Shift
4

The correct statements among the following are, Choose the correct answer from the options given below :

  1. A and B Only
  2. C and D Only
  3. B and D Only
  4. A and C Only
JEE Main 2026 (Online) 4th April Morning Shift
5

Correct statements from the following are Choose the correct answer from the options given below :

  1. A, B and C Only
  2. A, C and D Only
  3. A and C Only
  4. B and D Only
JEE Main 2026 (Online) 4th April Morning Shift
6

Match the LIST-I with LIST-II Choose the correct answer from the options given below :

  1. A-I, B-III, C-IV, D-II
  2. A-II, B-I, C-III, D-IV
  3. A-IV, B-II, C-I, D-III
  4. A-III, B-I, C-IV, D-II
JEE Main 2026 (Online) 4th April Morning Shift
7

Pairs of elements with the same number of electrons in their respective 4f orbital are [Atomic number. Eu-63, Gd-64, Dy-66, Ho-67, Tm-69, Yb-70, Lu-71, Hf-72] Choose the correct answer from the options given below :

  1. B and C Only
  2. A and B Only
  3. A and D Only
  4. A and C Only
JEE Main 2026 (Online) 4th April Evening Shift
8

Consider |x| is the difference in oxidation states of Mn in highest manganese fluoride and highest manganese oxide. The ions with |x| number of unpaired electrons from the following are : Choose the correct answer from the options given below :

  1. A and B Only
  2. C, D and E Only
  3. C and E Only
  4. B and E Only
JEE Main 2026 (Online) 4th April Evening Shift
9

Which of the following sets includes all the species that will change the orange colour of K2Cr2O7 in acidic medium ?

  1. Fe2+, Sn2+, I-, S2-
  2. S2-, Fe3+, I-, C2O42-
  3. Fe2+, NO2-, SO2, Sn4+
  4. Fe3+, SO42-, S2-, Sn4+
JEE Main 2026 (Online) 2nd April Morning Shift
10

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 2nd April Evening Shift
11

Among Fe2+, Fe3+, Cr2+ and Zn2+, the ion that shows positive borax bead test and with highest ionisation enthalpy is :

  1. Fe2+
  2. Zn2+
  3. Cr2+
  4. Fe3+
JEE Main 2026 (Online) 2nd April Evening Shift

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