StellarPeriods & Groups
The Periodic Table is an organized table which shows all of the elements we currently know. Elements on the periodic table are organized in terms of their atomic number, or number of protons. The higher the atomic number, the more further to the bottom and to the right the element will be.
The periodic table is also organized in periods and groups. Periods are horizontal rows along the periodic table. Every element in a period will have the same amount of shells with electrons, but not necessarily subshells. Groups are vertical columns in the periodic table, where every element in the group will have the same number of valence electrons. Valence electrons are simply the amount of electrons an element has on its outermost shell.