Learn: Atomic Structure and the Periodic Table

Welcome!Today we'll learn about atomic structure and the periodic table. These topics are key to understanding chemistry and the behaviour of elements.

What is an atom?An atom is the smallest unit of an element that retains its properties. It consists of a nucleus made of protons and neutrons, surrounded by electrons.

Subatomic particlesAtoms are made of three types of subatomic particles: protons (positively charged), neutrons (neutral), and electrons (negatively charged). Protons and neutrons are found in the nucleus, while electrons orbit around it.

What are isotopes?Isotopes are atoms of the same element with 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-12 and carbon-14 are isotopes of carbon.

Electronic configurationsThe electronic configuration shows how electrons are arranged in shells around the nucleus of an atom. Electrons fill shells starting with the lowest energy level. For example, sodium has an electronic configuration of 2,8,1.

Development of the periodic tableThe periodic table was developed by Dmitri Mendeleev. He organised elements by increasing atomic mass and grouped them based on similar properties. Today, elements are arranged by atomic number.

Groups and periodsElements are arranged in rows called periods based on their increasing atomic number. Columns are called groups, and elements in the same group have similar chemical properties due to having the same number of electrons in their outer shell.

Properties of metals and non-metalsMetals are generally shiny, good conductors of heat and electricity, and malleable. Non-metals are usually dull, poor conductors, and brittle. The position of an element in the periodic table helps determine if it is a metal or non-metal.

Review Time!Great work! You've learned about atoms, isotopes, electronic configurations, and the periodic table. Now let's test your understanding.