TRANSITION ELEMENTS

Multiple Choice Questions

Q1. The correct sequence of filling up orbitals is

A. 1s 2s 3s 2p 3p 4s 3d

B. 1s 2s 2p 3s 3p 4s 3d

C. 1s 2s 2p 3s 3p 3d 4s

D. 1s 2s 2p 3p 3s 4s 3d

Q2. The number of ligands present in the compound [Fe(H₂O)₆]³⁺ is

A. 6

B. 3

C. 2

D. 1

Q3. Which of the following statement best describes the similarities between copper and zinc?

A. They occur in their native state in nature.

B. Both metals dissolve in aqua-regia.

C. Both metals exhibit bivalency.

D. Both metals are white in colour.

Q4. Sonam prefer to make ear rings with silver and gold over other metals. The reason for her choice is:

A. Gold and silver are reactive

B. Gold and silver are inert

C. Gold and silver are attractive

D. Gold and silver are light

Q5. The elements of group 3 to 12 are known as

A. Halogens.

B. Alkali Metals.

C. Transition metals.

D. Alkaline Earth Metals.

Q6. All of the following substances are ferromagnetic in nature EXCEPT

A. Iron

B. Zinc

C. Nickle

D. Cobalt

Q7. How many sub-orbitals are present in L-shell?

A. 1

B. 2

C. 3

D. 4

Q8. Ammonium hydroxide is added to a solution. The solution formed a white precipitate which turned colourless in excess of ammonium hydroxide. Name the cation present in the solution.

A. Fe²⁺

B. Zn²⁺

C. Cu²⁺

D. Pb²⁺

Q9. From the following, which has a co-ordinate bond?

A. NH₃

B. H₃O⁺

C. H₂O

D. CO₃^2-

Q10. Tandin conducted an experiment to find out the presence of Fe³⁺ ions in a compound by adding NaOH. Which of the observations given below confirms this?

A. A dirty green ppt. is formed which is insoluble in excess of NaOH.

B. A reddish brown ppt. is formed which is insoluble in excess of NaOH.

C. A dull white ppt. is formed which is soluble in excess of NaOH.

D. A dirty green ppt. is formed which is soluble in excess of NaOH.

Questions

Q1. Fill in the blanks.

a) In an atom, the “p” orbital can accommodate maximum of ____________ electrons.

Ans.: six

b) The reagent used for dissolving noble metals is____________.

Ans.: Aqua regia.

c) The number of atoms or ions surrounding a central metal atom in a complex ion by means of a coordinate bond is called ____________.

Ans.: Coordination number

Q2. Write ONE difference for ferromagnetic and diamagnetic substance (magnetic properties)

Ans.:

Ferromagnetic	Diamagnetic
Attracted by magnet	Repelled by magnet

Q3. What will be the co-ordination number of Cu in the complex compound [Cu(NH₃)₄]²⁺ ?

Ans.: 4

Q4. Define:

i) Ligand

Ans.: It is a species which can use its lone pair of electrons to form a dative/coordinate bond with transition metal.

ii) Define oxidation number

Ans.: The number that represents the number of electrons that an atom can gain, lose or share when chemically bonding with an atom of another element. OR

The number represents the number of electrons lost or gained by an atom of that element in the compound.

Q5. Name the catalyst used in the following process:

i. Haber’s process

Ans.: Catalyst used is Fe (iron)

ii. Contact process

Ans.: Catalyst used is Vanadium Pentoxide

Q6. Write electronic configuration in s p d f notations using Aufbau’s principle for the following elements

i) ₁₀Ne

Ans.: 1s² 2s² 2p⁶

ii) ₂₀Ca

Ans.: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

iii) ₂₁Sc

Ans.: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹

iv) ₂₄Cr

Ans.: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵

iv) ₂₉Cu

Ans.: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d¹⁰

Q7. When sodium hydroxide is slowly added to the Iron (ll) sulphate solution, a dirty green precipitate is formed.

i. Write the balanced chemical equations for the reaction

Ans.: FeSO₄  +  2NaOH  →  Fe(OH)₂  +  Na₂SO₄

ii. Name the precipitate.

Ans.: Iron (II) hydroxide or Fe(OH)₂ 

Q8. A coordination compound is formed when a transition metal ion reacts with a ligand. Give TWO features of transition metal ion that favors the formation of co-ordinate bond.

Ans.:

a. High charge density or smaller cationic size

b. Vacant d-orbital to accept lone pairs of electrons from the ligands. OR

Empty d-orbitals OR incompletely filled d-orbitals

Q9. Scandium is not considered a transition metal although it’s a member of the d-block element.

Ans.: Scandium ion (Sc³⁺)has no electron in the d-orbital OR it has empty d-orbital

e.c.: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s⁰ 3d⁰

Q10. State Aufbau’s principle

Ans.: States that electrons are filled to the orbitals one by one in order of the increasing order of energies. OR

States that electrons are filled up in the lower energy orbitals before filling up the higher energy orbitals.

Q11. Transition metal ions are usually coloured.

Ans.:    Due to incomplete / (vacant) d-orbitals. Hence, while promoting electrons to higher energy levels, transition metal ion impart colour.

Q12. The transition metal responsible for the white colour of paper is titanium not zinc. Justify.

Ans.: Because titanium has the d orbital filled whereas zinc does not.

(White is also considered colourless)

Compiled from BCSE 2017-2021