Question

Which of the following arrangements does not represent the correct order of the property stated against it?

• A. $V ^{2+} < Cr^{2+} < Mn^{2+} < Fe^{2+}$: paramagnetic behaviour
• B. $Ni^{2+} < Co^{2+} < Fe^{2+} < Mn^{2+}$ : ionic size
• C. $Co^{3+} < Fe^{3+} < Cr^{3+} < Sc^{3+}$ : stability in aqueous solution
• D. $Sc < Ti < Cr < Mn$ . number of oxidation states

Hint:

Paramagnetic property is dependent on the number of unpaired electrons.

Answer 1

The Correct Option is A

The correct answer is Option A) \(V ^{2+} < Cr^{2+} < Mn^{2+} < Fe^{2+}\): paramagnetic behaviour

V\(^{2+}\) = 3 unpaired electrons 
Cr\(^{2+}\) = 4 unpaired electrons 
Mn\(^{2+}\) = 5 unpaired electrons 
Fe\(^{2+}\) = 4 unpaired electrons 
Hence, the order of paramagnetic behaviour should be 
\(\, \, \, \, \, \, \, \, V^{2+} < Cr ^{2+} = Fe^{2+} < Mn^{2 +}\) 
Ionic size decreases from left to right in the same period 
Paramagnetic property is dependent on the number of unpaired electrons. As the unpaired electrons increase in number, the paramagnetic property also increases.

Discover More From Chapter: D and F Block Elements

Answer 2

The correct answer is Option A) \(V ^{2+} < Cr^{2+} < Mn^{2+} < Fe^{2+}\): paramagnetic behaviour

Real Life Applications

Some real-life examples of d-block elements: 
1. Iron: It is found in hemoglobin, and also used in many other applications, such as making steel and magnets. 

2. Cobalt: It is found in vitamin B12, and is also used in making magnets and high-temperature alloys. 
3. Chromium: it is used to make stainless steel. 
4. Nickel: It is used to make coins and jewelry and also used in making stainless steel and other alloys. 

Question can also be asked as

1. What is the correct order of the properties of the elements in the d-block?
2. Which of the following arrangements is incorrect?
3. Which of the following arrangements does not follow the trend of the properties of the elements in the d-block?

Answer 3

The correct answer is Option A) \(V ^{2+} < Cr^{2+} < Mn^{2+} < Fe^{2+}\): paramagnetic behaviour

Paramagnetic behavior is a property observed in certain substances that possess unpaired electrons, leading to a weak attraction to an external magnetic field. Transition metal ions are known for their variable oxidation states and magnetic properties. 

Paramagnetic Behavior

• Paramagnetism arises from the presence of unpaired electrons in the outermost electron shells of atoms or ions.
• These unpaired electrons align their spins with an external magnetic field, resulting in a weak attraction.

Transition Metal Ions

• Transition metal ions exhibit a wide range of oxidation states and magnetic properties due to the availability of d-orbitals for electron configuration.
• Different oxidation states give rise to variations in the number of unpaired electrons and, consequently, their paramagnetic behavior.

Incorrect Order of Paramagnetic Behavior

• The given arrangement states V²⁺ < Cr²⁺< Mn²⁺< Fe²⁺ as the order of increasing paramagnetic behavior.
• However, this arrangement is incorrect and does not align with the expected behavior based on the electron configurations of these ions.

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Electron Configurations

• V²⁺ has three unpaired electrons (3d³), making it highly paramagnetic.
• Cr²⁺ possesses four unpaired electrons (3d⁴), indicating stronger paramagnetic behavior than V²⁺.
• Mn²⁺ has five unpaired electrons (3d⁵), exhibiting even stronger paramagnetic properties than Cr²⁺.
• Fe²⁺ contains four unpaired electrons (3d⁶), making it more paramagnetic than Mn²⁺.

The correct order of increasing paramagnetic behavior among V²⁺, Cr²⁺, Mn²⁺, and Fe²⁺ is: V²⁺ < Cr²⁺ < Fe²⁺ < Mn²⁺.