Question

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

Answer 1

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  As²⁻
As has 33 electrons and the two negatives shows now it has 35 electrons.