Rows track electron shells
Moving across a period fills related electron states.
Columns reveal chemical similarities
Elements in a group often share valence-electron patterns.
Metals and nonmetals occupy broad regions
Their electrical, mechanical and chemical properties differ systematically.
The table predicts behaviour
Position gives clues about reactivity, bonding and likely ion formation.
Source trail: IUPAC: periodic table
This page explains scientific concepts for general learning. It does not replace laboratory safety procedures, professional engineering guidance, or individualized medical advice.