CHEMISTRY REVIEW MATTER

What is Chemistry Chemistry - the study of the structure, composition and properties of matter & how matter interacts with other matter Matter – anything that has mass and occupies space (has volume)

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

Classifying Matter

MATTER Mixtures Made of more than 1 component… Pure Substances Made of 1 component… Elements Compound Homogeneous Heterogeneous Has one kind of atom. Eg. Copper, gold, oxygen Has more than one kind of atom bonded in a fixed ratio called a molecule Eg. Water, CO2 Contains more than one unevenly mixed ‘phase’ – you can see the individual parts. Contains one evenly mixed ‘phase’ – looks like 1 thing. Eg. Solution

The Periodic Table

The Periodic Table There 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.

How is it Organized? Periods: (horizontal rows) Numbered 1-7 Each period represents an energy level where electrons can be found Counting across a row to an element’s location tells how many electrons are in its outer shell Groups or families: (vertical columns) Groups are numbered from 1-18 Group members have similar chemical properties which get stronger as you go down a column. Eg. Alkali Metals

How is it Organized? Metals are on the left side Metals & Non-metals Metals are on the left side Non-metals are on the right side Exception: Hydrogen (H) is a non-metal Metalloids are the elements that are between the metals and non-metals – they have some properties of both.

Properties of Metals & Non-metals High lustre (shiny) Most are grey or silver in colour Malleable (hammer into sheets) Ductile (stretch into wire) Good conductors of heat and electricity Most are solids at room temp…except Hg…it’s a liquid! Properties of non-metals Low 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.

METALS NON-METALS

Main group elements: Groups 1,2,17 and 18 Alkali metals: Group 1 – very soft, very reactive, one valence electron Alkaline earth metals: Group 2 – somewhat soft, somewhat reactive, two valence electrons Halogens: Group 17 – very reactive non-metals, one short of a full set of valence electrons, diatomic molecules Noble gases: Group 18 – almost completely un-reactive or inert, full valence shell. Exist as monatomic gases

ATOMIC STRUCTURE REVIEW A chemical Symbol represents 1 atom of an element. eg: Al Atoms 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:

In the orbitals (shells) around nucleus Sub-atomic Particles Particle Symbol Location Charge Size Proton P In the nucleus Positive 1 Electron E In the orbitals (shells) around nucleus Negative Neutron N Neutral

Back to the Periodic Table 6 12 This is the Atomic Number or A This is the Symbol This is the Element’s Name CARBON This is the Atomic Mass or Z

And now the short form… OR… A Z 6 12 CARBON (C) (Atomic Number) (Atomic Mass) OR… 6 12 CARBON (C)

Bohr-Rutherford Diagrams Outer shell (orbital / energy level) called the Valence shell Maximum # of electrons at each energy level (inner to outer) 2, 8, 8… The Nucleus contains protons & neutrons

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!

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.