Q, R and S are adjacent elements in Period $3$ of the Periodic Table. Element R has the greatest first ionisation energy and the smallest melting point among these three elements. What are the identities of Q, R and S?
- AQ = Na, R = Mg, S = Al
- BQ = Mg, R = Al, S = Si
- CQ = Al, R = Si, S = P
- DQ = Si, R = P, S = S