The periodic table organizes elements by atomic number and recurring chemical behavior. It helps you predict
valence, bonding tendencies, reactivity patterns, and many physical properties at a glance.
Predict common ions and valence
Group trends often indicate typical charges (e.g., alkali metals form +1 ions; halogens often form −1).
Estimate reactivity
Metals get more reactive down a group; nonmetals often become more reactive up a group (with notable exceptions).
Understand periodic trends
Atomic radius, ionization energy, and electronegativity follow patterns across periods and down groups.
Build electron configurations
Blocks (s, p, d, f) map to the last filled subshell, which explains many similarities.
Choose materials and applications
Categories hint at properties: noble gases are inert, alkali metals are highly reactive, transition metals conduct well.