Write the chemical symbols for three different atoms or atomic anions with 35 electrons.

Bromine atom, Br has 35 electrons

In Se there are 34 electrons and if it gain one electron and get negative charge then it has 35 electrons. So the symbol of anion wit 35 electrons is

Se⁻ has 35 electrons

Another anion, no longer solid as quickly as back is As ²⁻

As has 33 electrons and the two negatives shows now it has 35 electrons.