M atter

1. Matter

2. Matter is all around you • It is anything that has mass (the amount of stuff) and volume (occupies space) • Exists in four different states or phases • It is made up of atoms, molecules and ions What is matter

3. Atoms or molecules are closely packed together and have the lowest kinetic energy • Often hard and brittle • Cannot often change their shape • Add heat and increase the KE, you can change the state Solids

4. Atoms or molecules can now move relative to each other • Liquids can ‘flow’ at room temperature • Have more KE and do not have a specific shape but will conform to the container it is in • Add more heat… Liquids

5. Molecules or atoms are widely spread apart • They move freely in the space they are in and can move with high speeds • They can bump into one another and just bounce off instead of joining together • These have the highest KE Gases

6. May be new to you Add even more energy and the electrons and neutrons can separate from one another and a ‘soup’ of positive ions and negative electrons are formed This is the plasma state Plasmas

7. When you add energy and you change the phase of a substance, this is called a physical change as you have NOT changed what the material is, just its state • Melting ice to water • Ripping a piece of paper, crushing a can • A physical change affects the form of a substance but not its composition and they are generally reversible Physical changes

9. Fireworks – Matches – Creating Precipitates • These occur on the molecular level and produces a new substance with different chemical properties from the original substances. • Are usually irreversible – can’t relight a match! • Heat/light may be released, color change may occur, an odor may occur, gas bubbles could be produced, sound can be created Chemical Change

11. The smallest unit of matter is the atom • The smallest particle of matter that retains its chemical properties • Consists of three particles Atoms

12. Positive particles • Found in the nucleus of the atom • Have a charge of +1 • Have a mass of 1amu (atomic mass unit) • The number of protons in an element is the same as the atomic number of that element Protons

13. Negatively charged particles • Found in an area outside the nucleus called the electron cloud • Have no mass • Have a charge of -1 • In a neutral atom there are an equal number of protons and neutrons so that the net charge is zero (0) electrons

14. Particles without a charge • Found in the nucleus • Have a mass of 1 amu • The total atomic mass of an element id the number of protons added to the number of neutrons neutrons

15. Oxygen is the element • 8 is the atomic number • 16 is the atomic mass • How many protons? • How many electrons? • How many neutrons? • Answer =

16. The element is sodium • The atomic number is 11 • The atomic mass is 23 • How many protons, electrons and neutrons?

17. Try these…