Question

Arrange the following elements in order of decreasing atomic size. 

Rank the atoms from the largest to smallest. To rank items as equivalent, overlap them. 

Al Cl Ar P K

Answer 1

Answer:- Largest atom Smallest atom

K > Al > P > Cl > Ar     

When we are moving from left to right in the periodic table that means in period the atomic size is going to decreases due to extra electron added to same energy level with increase in proton or nuclear charge which going to attract more or increases the electron fulling capacity towards the nucleus which causes decrease in size from left to right in the period.

From top to bottom in the group the atomic size going to increases due to increasing one new energy level or shell causes increase of the atomic size.