STUDY AREA 1 – The STUDY AREA 1 – The Periodic TablePeriodic Table

This area of study investigates the This area of study investigates the structure and behaviour of atoms, they structure and behaviour of atoms, they way they are arranged in and trends way they are arranged in and trends across the periodic table and introduces across the periodic table and introduces the concept of calculations involving the concept of calculations involving atoms.atoms.

THE KINETIC THEORY OF THE KINETIC THEORY OF MATTERMATTER

This theory explains the behaviour of This theory explains the behaviour of atoms whether they are in a solid, atoms whether they are in a solid, liquid or gaseous state. liquid or gaseous state.

But what is the theory?But what is the theory?

Kinetic theory states Kinetic theory states that:that:

All matter is made up of tiny, invisible moving All matter is made up of tiny, invisible moving particlesparticles

Particles of different substances have different sizesParticles of different substances have different sizes Lighter particles move faster than heavier ones at a Lighter particles move faster than heavier ones at a

given temperaturegiven temperature As the temperature increases, the particles move As the temperature increases, the particles move

fasterfaster In a solid state, the particles are close together and In a solid state, the particles are close together and

vibrate in fixed positionsvibrate in fixed positions In a liquid state, the particles are further apart, have In a liquid state, the particles are further apart, have

more energy and can move around each othermore energy and can move around each other In a gaseous state, the particles are far apart, move In a gaseous state, the particles are far apart, move

rapidly and randomly with greater energy and take up rapidly and randomly with greater energy and take up available space around themavailable space around them

Atomic theory timelineAtomic theory timeline

400BC: Democritus1808: John Dalton1897: Sir J.J Thompson1911: Ernest Rutherford1913: Niels Bohr1932: Sir James Chadwick2007: ?

Atomic structureAtomic structure

What are atoms made of?What are atoms made of? Where do we find information about Where do we find information about

each atom or element?each atom or element? What do the numbers and symbols What do the numbers and symbols

mean?mean? How are the elements arranged on the How are the elements arranged on the

periodic table?periodic table? electron

neutron

proton

The periodic tableThe periodic table

Who developed the periodic table?Who developed the periodic table? What patterns exist?What patterns exist?

Electron configurationElectron configuration Electrons are found in energy shells that Electrons are found in energy shells that

surround the nucleus (like layers around surround the nucleus (like layers around an onion)an onion)

The shells are numbered 1 – 7 The shells are numbered 1 – 7 HOWEVER, within each shell there are HOWEVER, within each shell there are sub-shells which fill up in a specific sub-shells which fill up in a specific order and are lettered s, p, d & f.order and are lettered s, p, d & f.

To make matters more complicated, To make matters more complicated, each sub shell consists of smaller each sub shell consists of smaller orbitals, each of which can only hold 2 orbitals, each of which can only hold 2 electrons.electrons.

Electron configurationElectron configuration Each shell can hold a total of 2nEach shell can hold a total of 2n22 electrons (n electrons (n

= shell No.)= shell No.) What is the order for filling each of the sub What is the order for filling each of the sub

shells? shells? □ □ 1s1s □ □ 2s2s □□□ □□□ 2p2p □ □ 3s3s □□□□□□3p3p □ □ 4s4s □□□□□□□□□□3d3d □□□□□□4p4p □ □ 5s5s

Electron configurationElectron configuration

Eg. Sodium (Na). Z=11 Therefore Eg. Sodium (Na). Z=11 Therefore there are 11 electrons to place in there are 11 electrons to place in energy shells. How.energy shells. How.

Na is in period 3, therefore must Na is in period 3, therefore must occupy 3 shells.occupy 3 shells.

Shell 1 = 2e, shell 2 = 8e and shell 3 Shell 1 = 2e, shell 2 = 8e and shell 3 = 1e = 1e

(group 1)(group 1) Written as 1s², 2s², 2p6, 3s1Written as 1s², 2s², 2p6, 3s1

Trends in the periodic Trends in the periodic tabletable

As you move across a period, the As you move across a period, the atomic number increases and more atomic number increases and more electrons are being added to the electrons are being added to the outer shell. outer shell.

What trends does this produce?What trends does this produce? What about as you move down each What about as you move down each

group. What trends are observed?group. What trends are observed?

IsotopesIsotopes

Why is the mass number for each Why is the mass number for each element on the periodic table not an element on the periodic table not an even number like the atomic number is?even number like the atomic number is?

Because for each atom, there are often Because for each atom, there are often more than 1 isotope. An isotope is an more than 1 isotope. An isotope is an element with the same number of element with the same number of protons, but different numbers of protons, but different numbers of neutronsneutrons

Eg. OEg. O1616 O O1717 O O1818

Quantities in chemistryQuantities in chemistry

Atoms are very, very, very etc. small. Atoms are very, very, very etc. small. So how do we calculate how much So how do we calculate how much of a substance to use in a reaction if of a substance to use in a reaction if we can’t count out a certain number we can’t count out a certain number of atoms to be used.of atoms to be used.

We use the ‘mass’ instead and We use the ‘mass’ instead and something called ‘a mole’something called ‘a mole’

Quantities in chemistryQuantities in chemistry When substances react, they do so in When substances react, they do so in

exact and reproducible amounts. exact and reproducible amounts. Consider this reaction C(s) + OConsider this reaction C(s) + O22(g) (g)

COCO22(g)(g) One atom of carbon (C) is reacting with One atom of carbon (C) is reacting with

one molecule of oxygen (Oone molecule of oxygen (O22) to produce ) to produce one molecule of carbon dioxide (COone molecule of carbon dioxide (CO22).).

If we knew the mass of the atoms and If we knew the mass of the atoms and molecules involved, we could predict the molecules involved, we could predict the quantities of reactants and products.quantities of reactants and products.

The ‘Mole’The ‘Mole’ The mole is one of the most important The mole is one of the most important

concepts in chemistry.concepts in chemistry. The mole is an amount of substance The mole is an amount of substance

containing a specified number of particles. containing a specified number of particles. This “specified” number is called This “specified” number is called Avogadro's Number and is equal to Avogadro's Number and is equal to

6.02 x 106.02 x 102323.. A mole of pure substance:-contains 6.02 x A mole of pure substance:-contains 6.02 x

10102323 elementary particles (atoms, elementary particles (atoms, molecules, ions) and has a mass (in grams) molecules, ions) and has a mass (in grams) equal to its relative atomic (Aequal to its relative atomic (Arr) or molar ) or molar mass (M)mass (M)

The ‘Mole’The ‘Mole’

Calculations involving moles.Calculations involving moles. The amount of substance (in mole) The amount of substance (in mole)

can be calculated from the mass of a can be calculated from the mass of a pure substance using the formula: pure substance using the formula: n = m/M n = m/M

Where: Where: n is the number of moles n is the number of moles m is the mass in grams m is the mass in grams M is the molar M is the molar mass in g Molmass in g Mol-1-1

STUDY AREA 2 - STUDY AREA 2 - MATERIALSMATERIALS

This study area examines the different This study area examines the different types of bonding that can occur between types of bonding that can occur between substances and how this bonding can substances and how this bonding can effect the chemistry of the substance.effect the chemistry of the substance.

BondingBonding

Strong types of bonding that form Strong types of bonding that form molecules include:molecules include:

ionic, covalent and metallicionic, covalent and metallic

Weaker forms of bonding Weaker forms of bonding betweenbetween molecules include:molecules include:

polar, hydrogen and dispersion polar, hydrogen and dispersion forcesforces

Metallic bondingMetallic bonding About 80% of the known elements are About 80% of the known elements are

metals metals Properties of Metals:Properties of Metals:Good conductors of electricityGood conductors of electricityGood conductors of heatGood conductors of heatShiny (lustrous) when cleanedShiny (lustrous) when cleanedMalleableMalleableDuctileDuctileGenerally high density (all solids except Generally high density (all solids except

mercury)mercury)Generally high melting pointGenerally high melting point

Why?Why?

Metallic bonding modelMetallic bonding modelMetal atoms form positive charged cations by losing their outer shell electrons. These electrons hang around to become delocalised electrons.

Delocalised electrons can flow throughout a metal structure but are always surrounding the positive cations to keep them balanced.

MODIFYING METALS TO MODIFYING METALS TO MAKE THEM MORE USEFULMAKE THEM MORE USEFUL

Few metals are used in their pure form. Few metals are used in their pure form. Most metals have been modified to Most metals have been modified to improve their performance in a improve their performance in a particular use.particular use.

Metals can be modified by:Metals can be modified by:alloying themalloying themchanging their crystal structurechanging their crystal structure

IONIC BONDINGIONIC BONDING

Ionic compounds (or salts) are usually Ionic compounds (or salts) are usually products of the combination of products of the combination of metals metals and non-metalsand non-metals..

Properties of Ionic Compounds:Properties of Ionic Compounds:

High melting temperatures (all solids at High melting temperatures (all solids at room temperature)room temperature)

Hard, but brittleHard, but brittle

Do not conduct electricity in the solid stateDo not conduct electricity in the solid state

Do conduct electricity when molten (or Do conduct electricity when molten (or dissolved)dissolved)

THE IONIC BONDING THE IONIC BONDING MODELMODEL

Na + Cl → NaCl

The Na+ and Cl- ‘ions’ arrange themselves into a 3D crystal lattice structure (like metals)

FORMULAE AND NAMING OF FORMULAE AND NAMING OF IONIC COMPOUNDSIONIC COMPOUNDS

What is the formula for sodium What is the formula for sodium chloride?chloride?

What is the name of MgO?What is the name of MgO?

What are the rules for finding the What are the rules for finding the formula or name of ionic substances?formula or name of ionic substances?

COVALENT BONDINGCOVALENT BONDING

Occurs between NON METALS onlyOccurs between NON METALS only Although non metals account for only Although non metals account for only

about 20% of the 100 or so elements, about 20% of the 100 or so elements, they combine to form over 90% of the they combine to form over 90% of the compounds we’ve named to date.compounds we’ve named to date.

There are 2 types of non metal There are 2 types of non metal substances:substances:

Molecular substancesMolecular substances

Covalent lattice substancesCovalent lattice substances

MOLECULAR MOLECULAR SUBSTANCESSUBSTANCES

Properties of Molecular SubstancesProperties of Molecular Substances

Low melting and boiling points (gases Low melting and boiling points (gases or liquids at room temperature)or liquids at room temperature)

Non conductors of electricityNon conductors of electricity

Generally poor solubility in waterGenerally poor solubility in water

Covalent bonding modelCovalent bonding model

Two fluorine atoms can bond by sharing their ‘unpared’ outershell electron

Can atoms share more than ONE electron?

Ionic V’s Covalent Ionic V’s Covalent BondingBonding

Representing covalent Representing covalent bondsbonds

Covalent molecules can be drawn as either electron dot Covalent molecules can be drawn as either electron dot diagrams or structural diagramdiagrams or structural diagram

H• + H• → H• + H• → HH::HH

H + H → HH + H → H--HH

H

H C H

H