Question

Consider the following five elements of the modern periodic table (atomic number of each is given in the parenthesis). P(4), Q(9), R(14), S(19), T(20). Which elements belong to the same period? Which elements belong to the same group? ​

Answer 1

Explanation:

those elements which have same number of shells are in same period

and elements which have same number of valence electrons are in same group

Answer 2

Answer:

i) P(4) , Q(9)

ii)P(4),T(20)

iii) Fluorine