The periodic table shows all the atoms that everything in the known universe is made from. It’s kind of like the alphabet in which only 26 letters, in different combinations, make up many thousands of ...

Give each student a Periodic Table of Energy Levels activity sheet. This table contains energy level models for the first 20 elements. The electrons are included only for the atoms at the beginning ...

Physicists have filled in some longtime blank spaces on the periodic table, calculating electron affinities of the lanthanides, a series of 15 elements known as rare earths.