Atomic Structure and the Periodic Table

The periodic table is your chemistry roadmap, and it's brilliantly organised to help you understand elements quickly. Metals live on the left side, whilst non-metals hang out on the right - this simple split makes remembering properties much easier.

There are 8 groups (vertical columns) that you need to know. Group 1 contains the alkali metals, Group 7 houses the halogens, and Group 0 (sometimes called Group 8) is home to the noble gases. Each group shares similar properties, which is dead useful for predicting how elements will behave.

Every atom contains three crucial sub-atomic particles: protons, neutrons, and electrons. Think of protons as the atom's identity card - they determine what element you're dealing with. Neutrons add mass but don't change the element's identity, whilst electrons orbit around the nucleus and determine chemical behaviour.

Quick Tip: The number of protons always equals the number of electrons in a neutral atom, keeping everything balanced!

Here's how to decode any element on the periodic table using three examples. For lithium (Li): mass number is 7, atomic number is 3, so you've got 3 protons, 3 electrons, and 4 neutrons $7-3=4$. Argon (Ar) shows mass number 39, atomic number 18, giving you 18 protons, 18 electrons, and 21 neutrons. Finally, magnesium (Mg) with mass number 24 and atomic number 12 contains 12 protons, 12 electrons, and 12 neutrons.