* Oxygen's natural state: Oxygen has 8 protons (positive charge) and 8 electrons (negative charge). This makes it neutral.

* Adding electrons: Adding 2 electrons means you now have 8 protons and 10 electrons.

* Calculating the charge: Since there are 2 more electrons than protons, the overall charge becomes -2.

Therefore, the charge of an oxygen atom with 2 added electrons is -2.