Transition elements are placed in which blocks?

1. Transition elements are placed in which blocks? +

Answer

Transition elements are placed in the d-block.

Detailed Explanation

Transition elements are the elements in which the differentiating electron enters the (n − 1)d orbital. They are located in the middle of the modern periodic table and correspond mainly to Groups 3–12.

General electronic configuration: (n − 1)d^1–10 ns^0–2

The four transition series are:

3d Series Sc → Zn
Period 4

4d Series Y → Cd
Period 5

5d Series La/Hf → Hg
Period 6

6d Series Ac/Rf → Cn
Period 7

The d-block contains metals with characteristic properties such as variable oxidation states, formation of coloured ions, complex formation, magnetic behaviour and catalytic activity.

Block-wise Classification

s-block: Groups 1–2
p-block: Groups 13–18
d-block: Groups 3–12
f-block: Lanthanoids and Actinoids

Transition elements → d-block → Groups 3–12

Important Exam Note

A transition element is not simply any element belonging to Groups 3–12. Strictly, a transition element has a partially filled d-subshell in its atom or in one of its common oxidation states. For example, Zn, Cd and Hg are d-block elements but are generally not considered transition elements because their d-subshell is completely filled in the atom and common +2 ion.

30 Related MCQs with Solutions

1. Transition elements belong to which block?

A. s-block

B. p-block

C. d-block

D. f-block

Answer: C. d-block

2. The d-block elements are mainly present in:

A. Groups 1–2

B. Groups 3–12

C. Groups 13–18

D. Only Group 18

Answer: B. Groups 3–12

3. The differentiating electron in transition elements enters the:

A. ns orbital

B. np orbital

C. (n−1)d orbital

D. nf orbital

Answer: C. (n−1)d orbital

4. Which series represents the first transition series?

A. 2d

B. 3d

C. 4d

D. 5d

Answer: B. 3d series
It extends from Sc to Zn.

5. The 3d transition series occurs in which period?

A. 3

B. 4

C. 5

D. 6

Answer: B. Period 4

6. The 4d series belongs to:

A. Period 4

B. Period 5

C. Period 6

D. Period 7

Answer: B. Period 5

7. The 5d transition series is associated with:

A. Period 4

B. Period 5

C. Period 6

D. Period 7

Answer: C. Period 6

8. Which of the following is a d-block element?

A. Na

B. Ca

C. Fe

D. Cl

Answer: C. Fe

9. Iron belongs to which block?

A. s-block

B. p-block

C. d-block

D. f-block

Answer: C. d-block

10. The general configuration of d-block elements is:

A. ns²np^1–6

B. (n−1)d^1–10ns^0–2

C. ns¹

D. (n−2)f^1–14ns²

Answer: B

11. Which element is the first member of the 3d series?

A. Ti

B. Sc

C. V

D. Cr

Answer: B. Scandium

12. Which element is generally considered the last member of the 3d series?

A. Fe

B. Co

C. Ni

D. Zn

Answer: D. Zn

13. Which block is located between the s- and p-blocks?

A. f-block

B. d-block

C. p-block

D. s-block

Answer: B. d-block

14. Transition metals are also called:

A. Inner transition elements

B. Representative elements

C. d-block elements

D. Noble gases

Answer: C. d-block elements

15. Which block contains lanthanoids and actinoids?

A. s-block

B. p-block

C. d-block

D. f-block

Answer: D. f-block

16. Which orbital is partially filled in typical transition elements?

A. s

B. p

C. d

D. f

Answer: C. d orbital

17. Which of the following is a transition metal?

A. K

B. Ca

C. Fe

D. Ar

Answer: C. Fe

18. Variable oxidation states of transition metals are mainly due to:

A. Similar energies of ns and (n−1)d orbitals

B. Very large atomic size

C. Absence of d electrons

D. Filled p orbitals

Answer: A

19. Which property is characteristic of many transition-metal ions?

A. Coloured compounds

B. Always colourless compounds

C. No complex formation

D. No magnetic behaviour

Answer: A. Coloured compounds

20. Which block contains elements with differentiating electrons entering d orbitals?

A. s-block

B. p-block

C. d-block

D. f-block

Answer: C. d-block

21. Which element is not generally classified as a transition element despite being in the d-block?

A. Fe

B. Cu

C. Zn

D. Cr

Answer: C. Zn
Zn has a completely filled 3d subshell.

22. Which group contains the transition elements in the modern periodic table?

A. 1–2

B. 3–12

C. 13–18

D. Only 18

Answer: B. Groups 3–12

23. Which is an example of a 3d transition element?

A. Fe

B. Kr

C. Br

D. Ca

Answer: A. Fe

24. Which series contains elements such as Y, Zr, Nb and Mo?

A. 3d series

B. 4d series

C. 5d series

D. 4f series

Answer: B. 4d series

25. Which series contains Hf, Ta, W and Re?

A. 3d

B. 4d

C. 5d

D. 4f

Answer: C. 5d series

26. Transition elements are located mainly in the:

A. Left side of periodic table

B. Centre of periodic table

C. Far right only

D. Bottom two rows only

Answer: B. Centre of periodic table

27. Which one is a characteristic property of transition elements?

A. Complex formation

B. Only +1 oxidation state

C. Always diamagnetic

D. No catalytic activity

Answer: A. Complex formation

28. The d subshell can accommodate a maximum of:

A. 2 electrons

B. 6 electrons

C. 10 electrons

D. 14 electrons

Answer: C. 10 electrons

29. Which element has the configuration [Ar] 3d⁵4s¹?

A. Cr

B. Mn

C. Fe

D. Co

Answer: A. Chromium

30. The best definition of a transition element is an element having:

A. Completely filled s-subshell

B. Partially filled d-subshell in atom or a common oxidation state

C. Only p electrons

D. Completely filled f-subshell

Answer: B
This is the standard definition of a transition element.

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