2.1 Models of Matter The Particle Theory p. 44

Building Blocks of Matter  Like Lego, all matter is made of small pieces that are called Particles  Particles can be arranged in many different ways, but no matter how we group particles, they will either be a pure substance, or mixture.

1. Pure Substances  A pure substance contains only one type of particle.  Aluminum foil – contains only aluminum.  Jar ‘A’ – contains only red M & M’s.  Table Salt – contains only NaCl (sodium chloride) particles.

2. Mixtures  A mixture contains at least two different pure substances.  Pizza – has bread, sauce, cheese, and other toppings.  Jar ‘B’ – contains different coloured jelly beans.  Jar ‘C’ – contains Crystal Light drink mix.

Classifying Mixtures  Not all mixtures are the same, as we saw with the Jelly Beans and the Drink Mix.  Solution (Homogeneous Mixture)  When substances mix together so well that they look like one substance.  Jar ‘C’ – it looks like one substance even though it contains water and drink mix.  Jar ‘D’ – water and oil are insoluble - they don’t mix at all.

Classifying Matter  Heterogeneous Mixture  When the parts of the mixture can be easily seen.  Jar ‘B’ – each of the various types of jelly beans can be clearly seen.

The Particle Theory  We’ve just described the first two principles of the Particle Theory: 1.All matter is made up of tiny particles. 2.All particles of one substance are the same. Different substances have different particles.

The Particle Theory  The next two principles of the Particle Theory explain how particles interact with one another.  What happens when you are low on energy?  

The Particle Theory  Now, if you have a little more energy …    Even more energy! You’ve just had three ‘Red Bulls’...  

The Particle Theory  Principle three states: 3.The particles are always moving, and the more energy they have, the faster they move.  This is why when we heat substances, they can change from Solid – Liquid – Gas, we’ve added energy.

The Particle Theory  Similar to how the earth has gravity, and attracts other things to it, particles attract other particles.  Do you think cooler, less energetic particles will attract as strongly as hotter and more energized particles?  

The Particle Theory  What you’ve just described is the fourth, and final principle! 4.There are attractive forces between the particles. These forces are stronger when the particles are closer together.

What are these particles?  What is a substance called if we can no longer break it down into smaller particles?  Examples of these particles are Aluminum, Oxygen, Hydrogen, Rhodium, Zinc, etc.  These are called...  ELEMENTS!!  Elements are pure substances that cannot be broken down into simpler substances.

What are these particles?  What if we have two or more elements combined in a fix amount?  Examples of these include NaCl, H 2 O, and CO 2.  These are called...  COMPOUNDS!!  Compounds are substances that contain two or more different elements in a fixed proportion.

Naming the ‘Particles’  The particles referred to by scientists are called atoms.  Each element is made of only one type of atom.  Atoms can combine with each other to form molecules.  Molecules can contain 2 atoms, or many thousands of atoms.

Questions  Page 47, questions 2, 3 & 4