Susan has a beaker with one mole of water and another beaker filled with one mole of hydrogen chloride. Compare the number of molecules that Susan has of each
substance.

Ratio is 1:1 ; they have same number of molecules.

Explanation:

One mole of any compound have same number of molecules, irrespective of their chemistry and composition, i.e. 6.022x10^23 . This number is known as Avogadro's Number.

So the beaker with one mole of water contains = 6.022x10^23 molecules ;

and beaker with one mole of Hydrogen chloride = 6.022x10^23 molecules.

The comparative ratio is 1:1.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8