Periodic table

High School

Definition

A chart that arranges all the chemical elements in order of increasing atomic number into rows (periods) and columns (groups). Elements in the same group have similar properties because they have the same number of outer electrons, which makes the table a powerful tool for predicting chemical behaviour.

Worked examples

Group 1 (Li, Na, K, Rb, Cs, Fr) all have 1 outer electron and react vigorously with water.

Elements in the same column share the same number of outer electrons, giving them similar chemical behavior.

Carbon (C) is atomic number 6, in Period 2, Group 14; it has 4 outer electrons.

The period tells how many electron shells; the group number reveals outer electrons and predicts reactivity.

Common mistakes

Elements in the same period have similar chemical properties → Elements in the same group (column) have similar chemical properties Period (row) indicates number of shells; group (column) indicates outer electrons, which govern chemical behavior.
Atomic number is the same as atomic mass → Atomic number counts protons; atomic mass includes protons and neutrons The periodic table is ordered by atomic number (proton count), not mass.
The table arranges elements alphabetically or by discovery date → The table arranges elements by increasing atomic number Atomic number order reveals the repeating (periodic) pattern of chemical properties.

Where you'll use it next

You'll use the periodic table throughout chemistry to predict bonding, reactivity, and compound formulas, and in physics and materials science to understand atomic structure and properties of matter.

Found in 1 StudyPug lesson

Master the Periodic Table: Your Gateway to Chemistry

Chemistry 11

Explore the periodic table's organization and structure in our engaging video. Learn how elements are arranged, understand their properties, and gain insights into chemical reactions. Perfect for beginners and curious minds alike!

11th Grade11th