Access to HE Diploma

1. Access to HE Diploma • Pharmacy and Biomedical Science • Introduction to Matter • Lesson 2

2. Hand in homework • Moles, Formulae and Equations workbook. • Experimental report – Density.

3. Assessment Criteria • 1.1 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 are • 1.4 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 examples • 2.2 Describe two differences between a compound and a mixture • 3.1 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 atoms • 4.3 Write the formulae for some simple and some complex compounds • 4.4 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 proton • 5.3 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 base • 6.1 Construct balanced chemical equations, full and ionic

4. Review Activity • Write down the names and symbols of the first 20 elements • Write down the definitions of the following words: • Element • Ion • Isotope

5. Review Activity • Magnesium, 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?

6. Review Activity • b. Explain why non metals are poor conductors of heat.

7. Today’s Aim • Understand that matter can be classified into elements, compounds and mixtures

8. Week 2 • 2.1 Classify substances as elements or compounds from their names • 2.2 State two differences between a compound and a mixture

9. Week 2 Reading • Access to Chemistry • Alan Jones, Mike Clement, AvrilHigton Elaine Goulding • ISBN 0 -85404-564-3 Inside the atom Pages 17 - 32

10. Classify substances as elements or compounds from their names • A mix of things to be classified into elements compounds or mixtures.

11. Element compound or mixture

12. Element compound or mixture

13. Element compound or mixture

14. Element compound or mixture

15. Element Definition • Write down your element definition here: • MariamaKoroma

16. Compound 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.

17. Mixture Definition • A 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.

18. Overview Homogeneous: Uniform in structure or composition throughout.

19. Cu Na He O O O H H These are elements! Atoms of same element Molecules of same element Hydrogen gas element copper element helium element ozone sodium element

20. 1.2 Write the names and symbols of the first 20 elements.

21. Hydrogen (H2) is a diatomic molecule. Ozone (O3) is a triatomic molecule. Molecules consisting of a few atoms are called polyatomic molecules.

22. O O O O H H O Examples of molecules (elements) S S S S S S S N N S

23. Classification 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. Metals and non-metals are grouped separately on the Periodic Table. There are some elements called metalloids which behave like both metals and non-metals.

25. Activity: Classify the physical properties of metals and non-metals

26. Summarising Elements Metals Non Metals Atoms Atoms Molecules

27. Cu H H What is a compound? A compound is a substance which is made up of two or more elementschemically combined together. • Chemical reactions taking place. Qn: Is this a compound? Qn: Is this a compound? Qn: Is this a compound? O It only contains one type of element. It only contains one type of element. O It is not chemically combined. H H O

28. O N H H H H H What is a compound? Water Ammonia gas Consists of two or more elements And They are chemically combined together!

29. Making compounds from their elements Example: Making iron sulphide compound compound elements heat Sulphur+ Iron  iron sulphide +  heat yellow grey black Iron sulphide does not have any common uses but does contribute to the colour of sludge at the bottom of ponds or lakes.

30. How do we name compounds? Rule 1 A 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

31. How do we name compounds? Rule 2 A 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

32. 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

33. How do we write chemical formula?Rule 1 For 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)

34. How do we write chemical formula?Rule 2 The number of atoms is written as a subscript, to the right of the atom’s symbol. • water (H2O, not H2O or 2HO) • magnesium carbonate (MgCO3, not MgCO3 or MgC3O)

35. How do we write chemical formula?Rule 4 The 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)

36. How do we calculate the number of atoms in a formula? Number of nitrogen (N) atoms = 1 x 2 = 2 Number of lead (Pb) atoms = 1 Pb(NO3)2 Number of oxygen (O) atoms = 3 x 2 = 6

37. Compounds can be Decomposed Heat can be used to break down compounds into elements or simpler compounds. Such a chemical reaction is called thermal decomposition. Oxygen Mercury(II) oxide

38. Summarizing • A compound is made up of two or more elementschemically 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 compound

39. Mixtures Definition 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.

40. Mixtures • Note 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.

41. Alloy: What is it?? • It is a mixture of metals with other elements • Alloy metals are generally stronger and better in physical properties • Examples • Steel (Iron + Carbon) • Stainless Steel (Nickel + Iron + Chromium + carbon) • Brass (Copper + Zinc)

42. Can you differentiate? Mixture of 2 elements-Alloy Molecules of an element Mixture of element & compound Compound Mixture of 2 elements

43. Conclusion An 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.

44. Difference between mixtures and compounds.

45. Difference between mixtures and compounds.

46. Difference between mixtures and compounds.

47. Difference between mixtures and compounds.

48. Comparison between mixtures and compounds Mixture Compound Separation /breakdown Components can be separated by physical methods Elements in a compound Cannot be separated by physical methods Properties (chemical / physical) Same properties as its components Properties are unique and different from its elements Energy Change No chemical change takes place when a mixture in formed A chemical reaction takes place when a compound is formed Mp / Bp Variable Fixed Composition Does not have a fixed composition Has a fixed composition

49. Challenge Time • Is mineral water an element, mixture or compound?

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