Elements and Compounds

Unit goals All matter is made up of tiny particles called atoms. There are many different atoms of which all substances are made. Substances made up of only one type of atom are called elements. Elements can be represented by a chemical symbol. All of the elements and their chemical symbols can be found on the Periodic Table. A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements. All compounds are molecules but not all molecules are compounds. Compounds have different properties than the individual elements of which they are made. A pure substance is made up of only one type of compound that cannot be broken down by physical means. A mixture is made up of different types of compounds each retaining their own properties.

Video on elements…

Matter and particles Everything around us is either a solid. Liquid or gas. What makes up a solid, liquid or gas?

Particles = atoms Another name for particles that make up solids, liquids and gases are called atoms.

Atoms There are many different types of atoms that exist here on Earth. They are the building blocks of all matter – both living and non living. Each element on the periodic table is made up of an atom. Each atom (element) is different…

Let’s investigate HOW each of the atoms (elements) are different… Copy the table on page 240 into your book with approximately 15-20 rows underneath. Once you have investigated the elements around the classroom, read page 239-240 and complete questions 1-8 on page 240.

Now that you know the first 20 elements of the periodic table… Each of the 20 elements you just learnt also have chemical symbols. The letter ‘C’ is the chemical symbol for Carbon

Now to learn 20 chemical symbols Element Symbol 1 Hydrogen H 11 Sodium Na 2 Helium He 12 Magnesium Mg 3 Lithium Li 13 Aluminium Al 4 Beryllium Be 14 Silicon Si 5 Boron B 15 Phosphorus P 6 Carbon C 16 Sulfur S 7 Nitrogen N 17 Chlorine Cl 8 Oxygen O 18 Argon Ar 9 Fluorine F 19 Potassium K 10 Neon Ne 20 Calcium Ca

It is important to know the symbols because later on, you will be able to understand things like this…

Atoms, Molecules and Compounds Molecule: A molecule is formed when two or more atoms join together chemically. + = Compound: A compound is a molecule that contains at least two different elements. + = molecule atom atom atom atom compound

Name the following: Molecule Compound Molecule Compound

Let’s make our own… Create, draw and colour any 10 combinations of a molecule and compound in your books.

What elements are the following molecules and compounds formed from? Using the internet, research what elements the following commonly used substances are made up from: Eg: Water = hydrogen + oxygen Salt Bleach Soap Coffee Honey Crude Oil (used for petrol) Steel Bubbles formed from pouring champagne. Air Name which of the substances above are molecules or compounds.