Question

The atomic radii of 3 elements P , Q , R of a period are 157 pm (picometere) , 104pm , and 125 pm respectively giving reason arrange these elements in increasing order of atomic num

Answer 1

The atomic radii decreases as we move across a period and the atomic number increases.
Increasing order of atomic radius is as follows:
R < Q <P
In period they are arranged in decreasing order of atomic radius and increasing order of atomic numbers.
The increasing order the of atomic numbers is as follows:
P < Q < R