Question

Which of the following is NOT true for alkaline earth metals?

• A. Their divalent ions have inert gas configuration.
• B. They are more electropositive than alkali metals.
• C. Alkaline earth metals are silvery white and soft.
• D. Their compounds are diamagnetic and colourless.

Hint:

Electropositivity decreases from left to right across a period. Group 1 (alkali) are the most electropositive elements.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
We need the statement that is NOT true for alkaline earth metals (Group 2: Be, Mg, Ca, Sr, Ba, Ra).

Step 2: Key Formula or Approach:
Compare properties: electropositivity (tendency to lose electrons) decreases across a period? Actually, down a group electropositivity increases. But comparing alkali metals (Group 1) and alkaline earth metals (Group 2) in the same period: Group 1 are more electropositive because they have lower ionization energy.

Step 3: Detailed Explanation:
- (A): True. Divalent ions \(M^{2+}\) have lost two electrons to attain the nearest inert gas configuration (e.g., \(Mg^{2+}\) has Ne configuration).
- (B): False. Alkali metals are more electropositive than alkaline earth metals because they have lower ionization enthalpy and higher reactivity.
- (C): True. They are silvery white, lustrous, and relatively soft (though harder than alkali metals).
- (D): True. Their compounds are generally diamagnetic (no unpaired electrons) and colourless (no d-d transitions).

Step 4: Final Answer:
The NOT true statement is option (B).