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Elements, Compounds, Mixtures

Part of the Atomic Structure section of Coddy's Chemistry journey. Lesson 2 of 45.

An element has one kind of atom. When atoms of different elements join, they make a compound: water, H₂O, is two hydrogen atoms joined to one oxygen atom.

A compound is a new substance with new properties. Sodium is a metal that fizzes in water and chlorine is a poisonous gas, yet together they make table salt, NaCl.

A mixture is only mixed, not joined, and can be separated again: boil salt water and the salt is left behind. Air is a mixture of gases.

Challenge

Glucose, the sugar your cells run on, has the formula C₆H₁₂O₆. How many different elements is it made of?

Try it yourself

FormulaCount the elements in C₆H₁₂O₆

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Atomic Structure

1Matter and Atoms

What Everything Is Made OfElements, Compounds, MixturesChemical Symbols Counting Atoms in a Formula Recap - Molecule Kit

4Electron Arrangement

Shells and the First 20 Valence Electrons Ionization Energy as Evidence Light from Atoms Subshells: s, p, d Aufbau, Hund and Pauli Writing Configurations Ions and the Exceptions Recap - Configuration Race

7Practice Problems

Recap - Potassium Oxide Recap - Helium from Rocks Recap - Uranium to Lead

2Models of the Atom

Dalton and Thomson Rutherford's Gold Foil The Nuclear Atom Bohr's Shells Recap - From Ball to Nucleus

5The Periodic Table

Mendeleev's Puzzle Groups and Periods Blocks: s, p, d, f Metals, Non-metals, Metalloids Alkali Metals Halogens Noble Gases Recap - Build the Table

3Inside the Atom

Protons Decide the Element Electrons and Charge Neutrons and Mass Number Nuclide Notation Ions Isotopes Radioactive Decay Relative Atomic Mass Recap - Mystery Particles

6Periodic Trends

Atomic Radius Ionic Radius Ionization Energy Trend Electronegativity Explaining Trends Recap - Mystery Element