Tag: general characteristics of first transition series

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Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which of the following group contains coloured ions?
1. $Cu^+$
2. $Ti^{4+} $
3. $Co^{2+}$
4.  $Fe^{2+}$

  1. $1,4$
  2. $3,4$
  3. $2,3$
  4. $1,2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$Cu^{+}$ and $Ti^{+4}$ have fully filled and empty d orbital respectively. Hence due to absence of unpaired electrons,they will be colourless. But $Fe^{+2}$ and $Co^{+2}$chave unpaired electrons. Hence they will be coloured.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Choose the correct answer from the alternative given.
Amongst $TiF _6^{2-}$, $CoF$,   $Cu _2$ $Cl _2$ and $NiCl$, which are the colourless species? (atomic number of Ti = 22, Co = 27, Cu = 29, Ni = 28)

  1. $CoF _6^{3-}$and $NiCl _4^{2-}$
  2. $TiF _6^{2-}$and $Cu _2Cl _2$
  3. $Cu _2Cl _2$ and $NiCl _4^{2-}$
  4. $TiF _6^{2-}$ and $CoF _6^{ 3-}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

TiF$ _6^{2-}$ -

The oxidation state of Ti is +4.
Electronic configuration of Ti$^{4+}$ is [Ar] 3d$^0 4s^0$.
So, unpaired e$^-$ s is present in d-orbitals so it is colourless.
Cu$ _2Cl _2$-
The oxidation state of Cu is +1.
Electronic configuration of Cu$^+$ is [Ar] 3d$^{10} 4s^0$.
So, no unpaired d e$^-$ s are present . Hence, the given compound is colourless.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Colour of transition metal ions are due to absorption of some wavelength. This results in:

  1. $d-f$ transition
  2. $s-s$ transition
  3. $s-d$ transition
  4. $d-d$ transition
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Colour of transition metal ions are due to absorption of the same wavelength. This results in $d-d$ transition.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

The coloured species is ?

  1. ${ VCl } _{ 3 }$
  2. ${ VOSO } _{ 4 }$
  3. ${ Na } _{ 3 }{ VO } _{ 4 }$
  4. $[{ V(H } _{ 2 }O) _{ 6 }]{ SO } _{ 4 }{ H } _{ 2 }O$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In Na3VO4, vanadium is in the +5 oxidation state (d0 configuration). The color arises from ligand-to-metal charge transfer (LMCT) rather than d-d transitions.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which of the following compounds are coloured due to charge transfer spectra?

  1. ${K} _{2}{Cr} _{2}{O} _{7}$
  2. $KMn{O} _{4}$
  3. $Cu{SO} _{4}.5{H} _{2}O$

  4. Both a and b
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Both potassium dichromate and potassium permanganate derive their intense colors from ligand-to-metal charge transfer (LMCT) transitions, where electrons are transferred from oxygen orbitals to empty metal d-orbitals. Copper sulfate color is due to d-d transitions, making options A and B the correct choices.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which of the following ion will give colourless aqueous solution ?  

  1. $Ni^{2+}$
  2. $Sc^{3+}$
  3. $Cu^{2+}$
  4. $Mn^{3+}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Solution:- (B) ${Sc}^{+3}$

Only the ions that have electrons in $d$-orbital and in which $d-d$ transition is possible will be coloured.
Electronic configuration of ${Sc}^{+3} \left( \text{At. no. = 21} \right) - 1 {s}^{2} 2 {s}^{2} 2{p}^{6} 3{s}^{2} 3 {p}^{6}$
Since it do not contains electrons in $d$-orbital and hence will not undergo $d-d$ transition and do not show colour.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Why are the compounds of transition metal generally coloured ?

  1. due to s being filled before d (Aufbau principle)

  2. Due to presence of unpaired electron

  3. unfilled d orbital

  4. d-d transition
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

coloured compound of transition elements is assosiated with partially filled (n-1)d orbitals. the transition metal ions containing unpaired d-electrons undergoes electronic transition from one d-orbital to another. during this d-d transition process the electrons absorb certain energy from the radiation and emit the remainder of energy as colored light. the color of ion is complementary of the color absorbed by it. hence, colored ion is formed due to d-d transition which falls in visible region for all transition elements.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Statement 1: Transition metal compounds are often colored.
Statement 2: They frequently possess partially filled d-orbitals.

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

  2. Both the Statement 1 and Statement 2 are correct, but Statement 2 is NOT the correct explanation of Statement 1.

  3. Statement 1 is correct, but Statement 2 is not correct.

  4. Statement 1 is not correct, but Statement 2 is correct.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transition metals are often coloured.

reason - they frequently posses partially filled of orbitals.