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Atoms & elements

Grade 7 · Science · Free lesson

Hey there! I'm Studyfin, and today we are going on a micro-adventure to explore the tiny building blocks that make up everything in the universe!

Have you ever wondered what you, your phone, and a cup of water have in common? They are all made of tiny, invisible building blocks called atoms. Atoms are so small that millions of them could fit on the head of a pin!

lithium

Inside every atom, there is a tiny 'solar system' structure. At the center is the nucleus, made of protons and neutrons, while even tinier electrons zip around the outside in constant, speedy orbits.

The Structure of an AtomBlue electrons orbiting the center nucleus

An element is a pure substance made of only one specific kind of atom. For example, a piece of pure gold contains only gold atoms, while the helium in a balloon contains only helium atoms.

Pure Element: Gold (Au)AuAuAuAuAuEvery single atom in this pure element is identical!
✏️ Worked example

Identify whether a container filled with water (H2O) is an element or not, and explain why.

  1. 1. Recall that an element is a pure substance made of only one type of atom.
  2. 2. Look at the chemical formula for water: H2O. This shows it contains Hydrogen (H) and Oxygen (O) atoms.
  3. 3. Because water is made of two different types of atoms bonded together, it is a compound, not a pure element!
atom
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