Introduction to Matter

Access to HE DiplomaPharmacy and Biomedical Science

Introduction to Matter

Lesson 2Hand in homeworkMoles, Formulae and Equations workbook.Experimental report Density.

Assessment Criteria1.1 Define an element giving examples.1.2 Write the names and symbols of the first 20 elements.1.3 Describe and explain what some of the general physical properties of metals and non-metals are1.4 Describe the relative position of metals, non-metals, groups and periods within the periodic table with examples.2.1 Classify substances as elements or compounds from their names giving examples2.2 Describe two differences between a compound and a mixture3.1 Describe protons, neutrons and electrons in terms of their relative charges and relative masses.3.2 Describe the distribution of mass and charge within an atom.3.3 Describe the contribution of protons and neutrons to atomic nuclei in terms of atomic number and mass number.3.4 Deduce the electronic configurations of atoms up to z = 36 and ions, given the atomic number and charge, limited to s and p blocks up to Z= 36.4.1 Describe ionic bonding as the electrostatic attraction between two oppositely charged ions including dot and cross diagrams.4.2 Describe a covalent bond as a pair of electrons shared between two atoms4.3 Write the formulae for some simple and some complex compounds4.4 Describe and interpret and/or predict physical properties in terms of the types motion and arrangement of particles (atoms, molecules and ions) and the forces between them, and the different types of bonding.5.1 Describe an acid as a species that can donate a proton.5.2 Describe a base as a species that can accept a proton5.3 Describe the reaction of an acid typified by hydrochloric acid with metals, carbonates bases and alkalis and interpret them using ionic equations to emphasise the role of H+(aq)5.4 Write a balanced equation for the reaction between two elements and between an acid and a base6.1 Construct balanced chemical equations, full and ionic

Review ActivityWrite down the names and symbols of the first 20 elements

Write down the definitions of the following words:ElementIonIsotopeReview ActivityMagnesium, steel and brass are all metals but only one of these substances is an element.

Which of these substances is an element?Why is this substance an element and the other two substances are not?

Review Activityb. Explain why non metals are poor conductors of heat.

Todays AimUnderstand that matter can be classified into elements, compounds and mixturesWeek 22.1 Classify substances as elements or compounds from their names2.2 State two differences between a compound and a mixture

Week 2 ReadingAccess to ChemistryAlan Jones, Mike Clement, Avril Higton Elaine GouldingISBN 0 -85404-564-3

Inside the atomPages 17 - 32

Classify substances as elements or compounds from their namesA mix of things to be classified into elements compounds or mixtures.Element compound or mixture

Element compound or mixture

Element compound or mixture

Element compound or mixture

Element DefinitionWrite down your element definition here:

Mariama KoromaCompound Definition A compound is a substance that can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means),

has properties that are different from its component elements, and

always contains the same ratio of its component atoms.

Mixture DefinitionA mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together. The atoms are not held together in a specific ratio.

Overview

Homogeneous: Uniform in structure or composition throughout.These are elements!Atoms of same elementCucopper elementNasodium elementHehelium elementMolecules of same elementHHydrogen gas elementOHOOozone1.2 Write the names and symbols of the first 20 elements.

Hydrogen (H2) is a diatomic molecule.

Ozone (O3) is a triatomic molecule.Molecules consisting of a few atoms are called polyatomic molecules.Examples of molecules (elements)HHNNOOOOOSSSSSSSSClassification of Elements Metals and Non-metals There are two major groups of elements metals and non-metals.

Iron is a metal. Oxygen is a non-metal.There are some elements called metalloids which behave like both metals and non-metals.Metals and non-metals are grouped separately on the Periodic Table.

Activity: Classify the physical properties of metals and non-metals MetalsNon-metalsNelsonHusseinRaymondDanielShaniceRobertaSummarisingElementsMetalsNonMetalsAtomsAtomsMoleculesWhat is a compound?A compound is a substance which is made up of two or more elements chemically combined together. Chemical reactions taking place.

CuQn: Is this a compound?It only contains one type of element.Qn: Is this a compound?HHIt only contains one type of element.HOHOOQn: Is this a compound?It is not chemically combined.What is a compound?OHHWater NHHHAmmonia gas Consists of two or more elementsAndThey are chemically combined together!Making compounds from their elements

Example: Making iron sulphide compoundSulphur + Iron iron sulphideelementscompound+yellowgreyheatheatblackIron sulphide does not have any common uses but does contribute to the colour of sludge at the bottom of ponds or lakes.How do we name compounds? Rule 1A compound made up of two elements has a name that ends in -ide. Sodium chloride made up of the elements sodium and chlorine Zinc oxide made up of the elements zinc and oxygen Carbon dioxide made up of the elements carbon and oxygen How do we name compounds? Rule 2A compound that contains hydroxide ions , OH (a negatively charged ion made up of oxygen and hydrogen) is named a hydroxide. Potassium hydroxide contains potassium ions and hydroxide ions Chemical Formula of a Compound

A compound can be represented by a chemical formula. The chemical formula states the types of atoms (i.e. elements) in the compound, the ratio of the different atoms in the compound. Types of atoms: hydrogen, oxygen

Ratio of H to O = 2:1 How do we write chemical formula?Rule 1For many compounds that contain both metallic and non-metallic elements, the symbol of the metallic element is written first. calcium oxide (CaO) sodium chloride (NaCl) magnesium carbonate (MgCO3) How do we write chemical formula?Rule 2The number of atoms is written as a subscript, to the right of the atoms symbol. water (H2O, not H2O or 2HO)

magnesium carbonate (MgCO3, not MgCO3 or MgC3O) How do we write chemical formula?Rule 4The oxygen atom is usually written at the end of the formula. water (H2O, not OH2) carbon dioxide (CO2, not O2C) nitric acid (HNO3, not O3NH) How do we calculate the number of atoms in a formula?Pb(NO3)2Number of nitrogen (N) atoms = 1 x 2 = 2Number of lead (Pb) atoms = 1Number of oxygen (O) atoms = 3 x 2 = 6Heat can be used to break down compounds into elements or simpler compounds. Such a chemical reaction is called thermal decomposition. Compounds can be Decomposed

Mercury(II) oxide Oxygen SummarizingA compound is made up of two or more elements chemically joined together

A compound has a fixed composition

Every compound has a unique chemical formula

A compound has a completely different properties from its elements

A chemical reaction (decomposition or electrolysis) is needed to separate the elements in the compoundMixturesDefinition of a mixture:

A mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together.MixturesNote that a mixture: consists of two or more different elements and/or compounds NOT chemically combined.Can be homogeneous or non-homogeneous can be separated into its components by physical means, and often retains many of the properties of its components.

Alloy: What is it??It is a mixture of metals with other elementsAlloy metals are generally stronger and better in physical propertiesExamplesSteel (Iron + Carbon)Stainless Steel (Nickel + Iron + Chromium + carbon)Brass (Copper + Zinc)Can you differentiate?CompoundMixture of element & compoundMixture of 2 elements-AlloyMolecules of an elementMixture of 2 elementsConclusionAn element is a pure substance which cannot be split up into two or more simpler substances by chemical means.

A compound consist of a fixed number of different kinds of atoms chemically combined together.

A mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together.Difference between mixtures and compounds.CompoundsE.g. Water H2OMixturesE.g.Salt solutionSeparationCannot be separated into its constituents by physical methods. Separation can only be done by chemical methods or by electricity.e.g. Water can only be separated into Hydrogen and Oxygen by Electrolysis.Can be easily separated into its constituents by physical methods.e.g. Salt can be obtained from its solution by evaporation. Water can be obtained by simple distillation.

Difference between mixtures and compounds.CompoundsE.g. Water H2OMixturesE.g.Salt solutionCompositionThe composition is fixed. The constituents (elements) in the compound are combined in definite amount.

e.g. To form one molecule of water, two atoms of Hydrogen and one atom of Oxygen is needed.Has no fixed composition. The amount of constituents in a mixture can vary.

e.g. The amount of salt added into the water to make salt solution can vary and vice versa.

Difference between mixtures and compounds.CompoundsE.g. Water H2OMixturesE.g.Salt solutionPropertiesThe physical and chemical properties of the compound is different from the properties of its constituents.

e.g. Hydrogen and Oxygen are gases while water is a liquid at room temperature and pressure.e.g. Water has a fixed melting and boiling point.

The mixture does not have its own properties. It has the average physical and chemical properties of the constituents that made it up. (Each constituents still retain its own properties)

e.g. The salt solution still retains its salt taste.e.g. Salt solution does not have a fixed melting or boiling point, but rather over a range of temperature.

Difference between mixtures and compounds.CompoundsE.g. Water H2OMixturesE.g.Salt solutionEnergy ChangeEnergy is usually given out or occasionally taken in when a compound is formed.Normally little or no energy is given out or taken in when a mixture is formed.

Comparison between mixtures and compoundsFixedVariableMp / BpHas a fixed compositionDoes not have a fixed compositionCompositionA chemical reaction takes place when a compound is formedNo chemical change takes place when a mixture in formedEnergy ChangeProperties are unique and different from its elementsSame properties as its componentsProperties(chemical / physical)Elements in a compound Cannot be separated by physical methodsComponents can be separated by physical methodsSeparation/breakdownCompoundMixtureChallenge Time Is mineral water an element, mixture or compound?

EXTRA!Human body is made up of 28 elements?About 99% our mass is made up of the 6 main elementsOxygen(65%)Carbon(18%)Hydrogen (10%)Nitrogen(3%)Calcium(1.5%)Phosphorus (1.5%)

Review Week 22.1 Classify substances as elements or compounds from their names2.2 State two differences between a compound and a mixture

WorkbookComplete section 2 pages 9 18Write 300 word essay on the structure of the atom.52Next Week Access to Chemistry pages 33 - 583.1 Describe protons, neutrons and electrons in terms of their relative charges and relative masses.3.2 Describe the distribution of mass and charge within an atom.3.3 Describe the contribution of protons and neutrons to atomic nuclei in terms of atomic number and mass number.3.4 Deduce the electronic configurations of atoms up to z = 36 and ions, given the atomic number and charge, limited to s and p blocks up to Z= 36.