Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

The Periodic Table - Groups and Periods

The periodic table is arranged into periods and groups.

The periodic table

The periodic table

  • The periodic table is the table that organises all the elements into groups and periods.
    • The elements are arranged in order of proton number, starting with hydrogen that has the proton number of 1.
Periods

Periods

  • A period is a row in the periodic table.
    • Elements in the same period have their valence electrons in the same shell.
  • The diagram highlights Period 3.
Period example

Period example

  • Magnesium and sulfur are in the same period.
    • In simple terms, they have the electron configuration 2,8,2 and 2,8,6 respectively.
    • So, their valence electrons are in the same shell.
Groups

Groups

  • A group is a column in the periodic table.
  • Elements in the same group have their electrons in similar orbitals.
    • They often have very similar properties.
    • A Group n element has n valence electrons.
      • E.g. Carbon is in Group 4 and has 4 valence electrons.
  • The diagram highlights Group 7.
Group example

Group example

  • The halogens are all in Group 7.
    • Fluorine's simplified electron configuration is 2,7.
    • Chlorine's is 2,8,7.
      • We see they both have the same number of valence electrons.
  • We also know that halogens have very similar chemical properties.

Periodic Table - Blocks

The periodic table can be organised into four sections. These are labelled s, p, d and f blocks.

The s block

The s block

  • The two leftmost columns make up the s block.
    • This is called the s block because elements in it have all their valence electrons in s orbitals.
    • Note, Helium is also an s block element because it has the electron configuration 1s2.
The p block

The p block

  • The six rightmost columns make up the p block.
    • This is called the p block because elements in the p block have a partially filled p sub-shell.
The d block

The d block

  • The d block lies between the s and p blocks.
    • Elements in the d block have a partially filled d sub-shell.
    • Elements in the d block are often called transition metals.
The f block

The f block

  • The f block is detached along the bottom of the periodic table.
    • Elements in the f block have a partially filled f sub-shell.
    • These elements are referred to as the lanthanides and the actinides (top and bottom row respectively).
Jump to other topics
1

Principles of Science I

1.1

Structure & Bonding

1.2

Properties of Substances

1.3

Cell Structure & Function

1.4

Cell Specialisation

1.5

Tissue Structure & Function

1.6

Working with Waves

1.7

Waves in Communication

2

Practical Scientific Procedures and Techniques

3

Science Investigation Skills

4

Principles of Science II

4.1

Extracting Elements

4.2

Relating Properties to use of Substances

4.3

Organic Chemistry

4.4

Energy Changes in Industry

4.5

The Circulatory System

4.6

Ventilation & Gas Exchange

4.7

Urinary System

4.8

Cell Transport

4.9

Thermal Physics

4.10

Materials

4.11

Fluids

5

Contemporary Issues in Science

Practice questions on The Periodic Table

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
Answer all questions on The Periodic Table

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium