What is the symbol of the species with number of electrons equal to 36 protons equal to 35 and neutrons equal to 45 ?

Answer

The atomic number of the element is equal to the number of protons`=35`
Thus, the element is bromine `(Br)`
Mass number = number of protons + number of neutrons `=35+45=80`
Since the specie contains one electrons more than the number of protons, it carries one unit negative charge.
`:.` The symbol of the species is `_(35)^(80) Br^(-)`