Players read questions about energy levels and score points by picking the correct element as the answer. Electrons are in regions around the nucleus that are different distances away from the nucleus ...

Students look more deeply into the structure of the atom and play a game to better understand the relationship between protons, neutrons, electrons, and energy levels in atoms and their location in ...

Elements in the same horizontal row are in the same period. The periods are numbered from top to bottom. The period number is the same as the number of occupied electron shells.

The covalent radius (a measure of how large individual atoms are) shows different trends if you are moving across a period or down a group. A comparison of the relative covalent radii of atoms is ...