Answer : A metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.
Explanation :
The group 16 element are oxygen, sulfur, selenium, tellurium and polonium.
The general electronic configuration of group 16 elements is,
![ns^2np^4](https://img.qammunity.org/2020/formulas/biology/middle-school/y04snkgaqlp03u6vcigmz7phheyrkovuw0.png)
As we now that there are total 6 electrons in p sub-shell. So, a metal in group 16 can become a chemically stable ion by gaining 2 electrons.
![M+2e^-\rightarrow M^(-2)](https://img.qammunity.org/2020/formulas/biology/middle-school/icupc8tyuz8l9nyit2x6714u7gu3qubtha.png)
Hence, a metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.