Season 1, Episode 1: Electrons are...negative?!

Caroline Christian, Ph.D.

One of the most important things to learn in chemistry class is that electrons are negatively charged. How can this be important to learn, you are asking yourself, when everyone knows this? I see this confused all the time, and I ask students, "What is the charge of an electron?" The reason this can be confusing is because of the charge of ions. Ions, now what are ions?! Just keep reading, it will all come clear soon! Cations are positively charged ions, usually metals that have lost electrons! Anions are negatively charged ions, usually nonmetals, which have gained electrons! When I see a positive sign (+) I naturally think something has been gained, not so in chemistry! Positive signs around ions means that something has been lost, in this case, electrons. And why when an atom loses an electron, does it become positively charged? Because electrons are negative! If you take away something negative from a neutral atom, it becomes positive. So the next time you are confused about the charges of ions, ask yourself, "What is the charge of an electron?"