Learn: Atomic Structure and the Periodic Table

Welcome!Today we'll explore Atomic Structure and the Periodic Table. This topic is essential for understanding how elements are organised and interact in Chemistry. Let's dive in and learn step by step!

What is Atomic Structure?Atoms are the building blocks of all matter. They are made up of three main subatomic particles: protons, neutrons, and electrons. Protons and neutrons are found in the nucleus, while electrons orbit around it in shells.

Subatomic ParticlesThe three key subatomic particles are:Protons — Positively charged particles found in the nucleus.Neutrons — Neutral particles found in the nucleus; they add mass to the atom.Electrons — Negatively charged particles that orbit the nucleus in energy levels or shells.The number of protons defines the element, while the electrons determine the chemical properties.

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 the same atomic number but different mass numbers.For example, carbon has two common isotopes: carbon-12 and carbon-14. Both have 6 protons, but carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons.

Electronic ConfigurationsElectrons are arranged in energy levels or shells around the nucleus. The first shell can hold up to 2 electrons, the second can hold up to 8, and the third can hold up to 8 before moving to the next shell.For example, the electronic configuration of oxygen (atomic number 8) is 2, 6 — two electrons in the first shell and six in the second shell.

The Periodic TableThe Periodic Table is a way of organising elements based on their atomic number. Elements in the same column (called groups) share similar chemical properties. Rows are called periods, and they represent the number of energy levels or shells in an atom.For example, group 1 elements like lithium and sodium are highly reactive metals, while group 18 elements like helium and neon are unreactive noble gases.

Review Time!Fantastic work! We've covered atomic structure, isotopes, electronic configurations, and the periodic table. Let's test your knowledge with a few review questions.