Atoms and other Building Blocks of Matter by Dr H - W Winter Yellow slides Complete the tasks on your worksheets Blue slides Just read and enjoy

Atomic Theory An atom is an incredibly small building block of matter. Atoms are so small that we cannot see them, even with the best microscopes in the world.

ATOMS ARE EVERYWHERE Name 3 substances that are made of atoms But, having said that ……… ATOMS ARE EVERYWHERE Name 3 substances that are made of atoms

How Many Atoms? Roughly how many atoms do you think there are in a teaspoon of sulfur (about 5g)? 100000 000000 000000 000000 (or about 1023) There are over 100 different types of atoms. Each one forms a different chemical element. These elements are listed in the periodic table.

Atoms can now be “seen” using special technology Image of individual atoms in Mica (Image courtesy of Veeco Instruments Inc http://www.veeco.com)

Two Examples of Atoms The Hydrogen Atom The Carbon Atom electron protons & neutrons proton electrons

Atoms are made from sub-atomic particles 1. Protons (+ electric charge), p 2. Electrons (– electric charge), e 3. Neutrons (no charge), n Protons and neutrons have about the same mass. Electrons have about 2000 times less mass than protons. Electrical Forces produce an attraction between the electrons and the protons in the nucleus. This is because they are oppositely charged.

Table of Sub-Atomic Particles Name Mass (mass units) Charge on Particle Where found Symbol Proton 1 + Nucleus p+ Electron 1/2000 - Electron shells e- Neutron no Have you finished copying the information?

Elements An element is a substance that can not be separated or broken down into simpler substances by chemical means. A group of atoms are known as a chemical element if they all have the same number of protons in their nucleus. Copper is an element. Oxygen is another. Can you name 5 more elements?

Hydrogen All Hydrogen atoms have 1 proton. They also have 1 electron. The electron orbits the proton in an ‘electron shell’ at more than half the speed of light (like satellites around Earth). proton

Properties of Elements

Carbon 6 electrons are found in the electron shells: 4 in the 2nd shell 2 in the 1st shell 6 protons and 6 neutrons make up the nucleus Most of the atom is empty space The nucleus is the heaviest part of the atom.

The First 20 Elements of the Periodic Table No Symbol Name Help 1 H Hydrogen Harry 2 He Helium He 3 Li Lithium Likes 4 Be Beryllium Beer 5 B Boron By 6 C Carbon Cupsfull 7 N Nitrogen Not 8 O Oxygen Over 9 F Fluorine Frothy 10 Ne Neon Nelly’s No Symbol Name Help 11 Na Sodium Naughty 12 Mg Magnesium MG 13 Al Aluminum Always 14 Si Silicon Sits 15 P Phosphorus Parked 16 S Sulfur So 17 Cl Chlorine Cleverly 18 Ar Argon Around 19 K Potassium K-Block 20 Ca Calcium Carpark

Types of Particles Atoms Atoms are single particles with no charge. H Hydrogen atom O Oxygen atom

Types of Particles Molecules Molecules are formed when 2 or more atoms connect to each other through their electrons (called bonding). H2 Hydrogen molecule H2O Water molecule

Types of Particles Ions Ions are atoms (or a group of atoms) that have gained or lost electrons and become a charged particles. Cl- Chloride ion Na+ Sodium ion SO42- Sulfate ion OH- Hydroxide ion

Types of Matter Elements Elements are pure substances made up of only one type of atom. An element can be made of single atoms (e.g. Helium He) An element can be made of molecules (e.g. Nitrogen N2)

Types of Matter Compounds Compounds are formed when two or more different types of atom chemically combine together. Oxygen and Hydrogen combine to form water

Types of Matter Pure Substance Pure substances are made up of only one type of particle. He Helium atoms H2 hydrogen molecules H2O water molecules

Types of Matter - Mixture Air: Salt Water: + Mixtures contain several different particles blended together. Air: 78% N2 21% O2 1% Ar 0.04% CO2 Salt Water: - + H2O Cl- (chloride ions) Na+ (sodium ions)

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