Elements P, Q, R, and S have atomic numbers 11,15,17 and 18 respectively. Which of them are reactive non-metals?
A. P and Q
B. P and R
C. Q and R
D. R and S
Answer:C
Elements P, Q, R, and S have atomic numbers 11,15,17 and 18 respectively. Which of them are reactive non-metals?
A. P and Q B. P and R C. Q and R D. R and S