An element \'X\' has mass number 35 and numbers of neutrons 18.How to find its period number..

An element \'X\' has mass number 35 and numbers of neutrons 18.How to

1.	An element \'X\' has mass number 35 and numbers of neutrons 18.How to find its period number..
Answer» Cl 17 Yup sorry its cl 17 chlorine It is chlorine...and period no.3 No. Of protons = mass no.- no of neutronSo it\'s no. Of protons is 17 so it is CHLORINE. 18 which is ar