2 What is ChemistryChemistry - the study of the structure, composition and properties of matter & how matter interacts with other matterMatter – anything that has mass and occupies space (has volume)
3 PROPERTIES OF MATTER: Physical Properties Can be determined without altering chemical composition of the substance.Qualitative properties are observed with the senses (not measured).Ex. colour, odour, taste, lustre, malleability, ductility, viscosity, form, texture.Quantitative properties are numerical measurements.Ex. density, boiling/melting point, solubility, volume, weight.Chemical Properties Describe how matter behaves in the presence of other substances, or when subjected to fire, heat, light, pressure or electricity.Ex. - magnesium reacts with hydrochloric acid to produce hydrogen gas - glass does NOT react to this acid
5 MATTERMixturesMade of more than 1 component…Pure SubstancesMade of 1 component…ElementsCompoundHomogeneousHeterogeneousHas one kind of atom.Eg. Copper, gold, oxygenHas more than one kind of atom bonded in a fixed ratio called a moleculeEg. Water, CO2Contains more than one unevenly mixed ‘phase’ – you can see the individual parts.Contains one evenly mixed ‘phase’ – looks like 1 thing.Eg. Solution
7 The Periodic TableThere are 118 elements on the Periodic Table. 92 of them are naturally occurring.All matter in the universe is made up of at least 1 element.
8 How is it Organized? Periods: (horizontal rows) Numbered 1-7 Each period represents an energy level where electrons can be foundCounting across a row to an element’s location tells how many electrons are in its outer shellGroups or families: (vertical columns)Groups are numbered from 1-18Group members have similar chemical properties which get stronger as you go down a column. Eg. Alkali Metals
9 How is it Organized? Metals are on the left side Metals & Non-metalsMetals are on the left sideNon-metals are on the right sideException: Hydrogen (H) is a non-metalMetalloids are the elements that are between the metals and non-metals – they have some properties of both.
10 Properties of Metals & Non-metals High lustre (shiny)Most are grey or silver in colourMalleable (hammer into sheets)Ductile (stretch into wire)Good conductors of heat and electricityMost are solids at room temp…except Hg…it’s a liquid!Properties of non-metalsLow lustre (dull)Various colours (including colourless)Brittle (shatter when hammered)Not ductile (shatter when stretched)Poor conductors (are insulators)Mostly solids and gasses at room temp.
12 Main group elements: Groups 1,2,17 and 18 Alkali metals: Group 1– very soft, very reactive, one valence electronAlkaline earth metals: Group 2– somewhat soft, somewhat reactive, two valence electronsHalogens: Group 17– very reactive non-metals, one short of a full set of valence electrons, diatomic moleculesNoble gases: Group 18– almost completely un-reactive or inert, full valence shell. Exist as monatomic gases
13 ATOMIC STRUCTURE REVIEW A chemical Symbol represents 1 atom of an element. eg: AlAtoms are not solid spheres as first thought, the majority of an atom is empty space! What gives matter “solidness” is the tiny subatomic particles that make up atoms.There are three types of subatomic particles:
14 In the orbitals (shells) around nucleus Sub-atomic ParticlesParticleSymbolLocationChargeSizeProtonPIn the nucleusPositive1ElectronEIn the orbitals (shells) around nucleusNegativeNeutronNNeutral
15 Back to the Periodic Table 612This is the Atomic Number or AThis is the SymbolThis is the Element’s NameCARBONThis is the Atomic Mass or Z
16 And now the short form… OR… A Z 6 12 CARBON (C) (Atomic Number) (Atomic Mass)OR…612CARBON (C)
17 Bohr-Rutherford Diagrams Outer shell (orbital / energy level)called the Valence shellMaximum # of electrons ateach energy level(inner to outer) 2, 8, 8…The Nucleus contains protons & neutrons
18 How to Draw a Bohr-Rutherford Diagram First you need to determine how many protons, electrons and neutrons you have: (PEN)Look at the Periodic Table:The atomic number = the number of protons (+) & the number of electrons(-) (# of + = # of -)The atomic mass can help you determine the number of neutrons:(Neutrons = atomic mass – atomic #)All that’s left is to draw the diagram!
19 How to Draw a Bohr-Rutherford Diagram for ANY Element. 1. Figure out how many protons, electrons and neutrons there are in one atom of the element.2. Draw the nucleus (a small circle).Inside the nucleus write the number of protons and neutrons.3. Calculate the number of orbitals you will need by following the limits on the number of electrons each orbital can have.4. Draw the orbitals as rings around the nucleus.5. Draw the electrons (as coloured-in circles) on the orbitals.