Question

An atom has an atomic number 17 and atomic mass number 35. How many neutrons are present in its nucleus

Answer 1

Neutrons = Mass number - Atomic number

Okay so the mass number is the number of protons + the number of neutrons. (The top number of each element in the periodic table).

Since atoms have no overall charge, we say the number of protons is equal to the number of electrons. This is the ATOMIC NUMBER. (The bottom number of each element on the periodic table).

So your atom has 17 electrons and the mass number is 35.
The number of protons is 17, (since it's the same number as electron number).
The number of neutrons is 35-17 = 18.
The atomic number is 17.

The element you have is CHLORINE.