Answer:
The Atomic number is 17 and Mass number is 35
Explanation:
So, For Atomic number
Atomic Number = No. of protons = No. of electrons = 17 (Which is Chlorine {Cl} )
Now, For Mass number
Mass number = No. of protons + No. of neutrons
Mass number = 17 + 18 = 35
Thus, The Atomic number is 17 and Mass number is 35
-TheUnknownScientist 72