Looking for a quick definition?
We’ve got loads of key subject terms in our subject glossaries. There are three ways of finding what you are looking for:
- First click on the letters of the alphabet to browse for terms.
- Select a subject from the drop-down menu above to filter the terms by Subject.
- Or lastly, type the term you are looking for into the search box.
Here are some examples of the kinds of definitions you’ll find on this page.
the number of protons in the nucleus of an atom, which determines which element it is. In a...
the radius of an atom from the nucleus to the outermost electrons.
states that the orbital with the lowest energy is the orbital that fills first.
a process whereby molecules combine automatically to form new ions as in the case of water.