Answer: Both form nitrides (Li 3 N and Mg 3 N 2 ), have similar solubility trends, and form covalent organometallic compounds.
- A Both form nitrides (Li<sub>3</sub>N and Mg<sub>3</sub>N<sub>2</sub>), have similar solubility trends, and form covalent organometallic compounds
- B Both generally exist as ordinary solid metals under standard everyday room conditions in routine practice
- C Lithium uniquely possesses exactly two valence electrons in its single outer shell overall in most cases under typical conditions
- D Both metals react with plain cold water at exactly the same observable vigorous rate according to standard textbooks
Correct answer: A. Both form nitrides (Li<sub>3</sub>N and Mg<sub>3</sub>N<sub>2</sub>), have similar solubility trends, and form covalent organometallic compounds
Explanation: Li resembles Mg: both form nitrides directly, both LiF and MgF<sub>2</sub> are sparingly soluble, both LiOH and Mg(OH)<sub>2</sub> are weak bases, and Li<sub>2</sub>CO<sub>3</sub>/MgCO<sub>3</sub> decompose on heating.
Each s-block metal ion emits a characteristic flame colour because heating excites electrons to higher energy levels; light is emitted as they fall back, with the colour determined by the specific energy gap.
Concept context
Group 1 (alkali metals) and Group 2 (alkaline earth metals). Learn their reactions with water and air, important compounds like NaOH, Na₂CO₃, and CaCO₃, and anomalous behaviour of lithium and beryllium.