Answer: Calcium.
- A Calcium
- B Lithium
- C Rubidium
- D Caesium
Correct answer: A. Calcium
Explanation: Calcium (as Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>) is the main mineral in bones and teeth, and is vital for nerve and muscle function.
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.