Which of the following atoms has the larhest atomic radius na k mg ca

Explanation:

Atomic size

in is defined  as size of on atom or distance from nucleus to outermost shell of an atom.  

 ALONG GROUP -->  it increases.  

For example:- Consider 1st group

Li – 3  2,1    K,L  

Na- 11  2,8,1  K, L, M  

K- 19  2, 8, 8, 1  K,L, M, N  

As we move down the group. , every time a new shell is being added due to which size of an atom increases.  

Along  period - it decreases.  

For example:- consider 3rd period  

Na  Mg  Ar  Si  

2,8,12,8,22,8,32,8,4  

We see every time, a new electron is added to the same shell due to which nuclear charge increases and size decreases.  

That is the reason ,In the above asked question : out of all K is bigger .

- both b and d.

-since b and d are the closest coastlines then that makes it the most affected.

< 3

it would be a gas formation