Learn: Atomic Structure and the Periodic Table

Welcome!Today we'll explore Atomic Structure and the Periodic Table. This topic helps us understand the building blocks of matter and how elements are organised.

What is an atom?An atom is the smallest unit of an element that retains its properties. Atoms consist of three subatomic particles: protons, neutrons, and electrons.

Subatomic ParticlesProtons have a positive charge and are found in the nucleus. Neutrons have no charge and are also in the nucleus. Electrons are negatively charged and move in shells around the nucleus.

What are isotopes?Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means they have different mass numbers but identical chemical properties.

Electronic ConfigurationThe electronic configuration shows how electrons are arranged in shells around the nucleus. Electrons fill the shells starting with the closest to the nucleus, following the 2, 8, 8 pattern.

The Development of the Periodic TableThe Periodic Table arranges elements by increasing atomic number. Dmitri Mendeleev originally organised it by atomic mass, leaving gaps for undiscovered elements. Modern tables use atomic number and group elements by their properties.

Groups and PeriodsGroups are columns in the Periodic Table and show elements with similar properties. Periods are rows that represent the number of electron shells an atom has.

Review Time!Great work! You've learned about atoms, isotopes, electronic configurations, and the Periodic Table. Let's test your understanding with a few questions.