Question

An element P (atomic number 20) reacts with an element Q (atomic

number 17) to form a compound. Answer the following questions

giving reason :

Write the position of P and Q in the Modern Periodic Table

and the molecular formula of the compound formed when P reacts

with Q.

Answer 1

position of element P:
group 2
period 4

position of element Q:
group 17
period 3

as element P has 2 electrons in its outermost shell and element Q has 7 electrons in its outermost shell then by reacting P n Q we get PQ2.