Structure of the Periodic Table
Specification Reference S3.1.1
Quick Notes
- The periodic table is arranged in periods (horizontal rows) and groups (vertical columns).
- Elements are classified as:
- Metals: left and centre
- Metalloids: on the "stair-step" line (e.g., B, Si, As)
- Non-metals: top right
- The table is divided into blocks, based on the sublevel of the outermost electron:
- s-block: Groups 1–2 + helium
- p-block: Groups 13–18
- d-block: Transition metals (Groups 3–12)
- f-block: Lanthanides and actinides (bottom of the table)
Full Notes:
Periods and Groups
- Periods: Horizontal rows numbered 1 to 7
- Show increasing atomic number from left to right
- Elements in the same period have the same number of electron shells
- Groups: Vertical columns numbered 1 to 18
- Elements in a group have similar chemical properties
- Same number of valence electrons
Blocks of the Periodic Table
The blocks correspond to the sublevel (orbital type) in which the outermost electron is in:
| Block | Sublevel | Elements Included | Notes |
|---|---|---|---|
| s | s | Groups 1–2 + Helium | Includes highly reactive metals and hydrogen |
| p | p | Groups 13–18 | Includes metalloids and non-metals |
| d | d | Transition metals (Groups 3–12) | Known for variable oxidation states |
| f | f | Lanthanides + Actinides | Typically shown below the main table |
Types of Elements
- Metals
- Found on the left and centre of the table
- Good conductors, malleable, ductile, often form cations
- Non-metals
- Found on the upper right, including Groups 14–18
- Poor conductors, often gases or brittle solids, tend to form anions
- Metalloids
- Elements with intermediate properties
- Lie along the “stair-step” line between metals and non-metals
- Common metalloids: B, Si, Ge, As, Sb, Te
Location Overview
| Region | General Location |
|---|---|
| Metals | Left and centre (Groups 1–12) |
| Non-metals | Upper right (Groups 14–18) |
| Metalloids | Along diagonal line between metals and non-metals |
| Transition metals | Centre of table (d-block) |
| Inner transition metals | Bottom two rows (f-block) |
Summary
- The periodic table is logically arranged based on atomic number and electron configuration.
- It is divided into periods, groups, and blocks which help predict chemical behaviour.
- Metals, non-metals, and metalloids each occupy distinct regions and show characteristic properties.