1) Atomic radius (pm) of Al, Si, N and F respectively is A) 117,143,64,74 B) 143,117,74,64 C) 143,47,64,74 D) 64,74,117,143 Answer: Option BExplanation: Al, Si belong to 3rd period of the periodic table while N, and fluorine to second period. The size of elements decreases from left to right in a period hence the order of size is Al> Si > N > F
