Access to HE Diploma

1. Access to HE Diploma • Pharmacy and Biomedical Science • Introduction to Matter • Lesson 4

2. Hand in homework • Moles, Formulae and Equations workbook. • Use spdf notation to write the electronic configuration for the first 20 elements

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 Explain how the following rules effect electron configuration. • Aufbau principle • Pauli Exclusion Principle • Hund’s Rule

5. Review Activity • Draw an Aufbau diagram for the following elements. • Lithium • Sodium • Potassium

7. Review Activity Draw a diagram to show how the diagonal rule affects the electron orbital filling order.

9. Today’s Aim • Recognise that chemical reactions involve outer shell electrons to produce ionic and covalent compounds and appreciate the significance of noble gas electron arrangement

10. Week 4 • . 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.

11. Week 4 Reading • Access to Chemistry • Alan Jones, Mike Clement, AvrilHigton Elaine Goulding • ISBN 0 -85404-564-3 Atoms and Ions Pages 55- 73

12. 4.1 Describe ionic bonding as the electrostatic attraction between two oppositely charged ions including dot and cross diagrams.Ionic Bonding • An ionic bond is a chemical link between two atoms caused by the electrostatic force between oppositely-charged ions in an ionic compound. • Are made up of: • a metal ion and a nonmetal ion. • A metal ion and polyatomic ions. • Exception to this rule is hydrogen fluoride. This is determined by the significant difference in electronegativity between hydrogen and fluorine.

13. Ionic Bonds

14. Valence Electrons • We have already encountered valence electrons on page 11 of the moles and formulae workbook. • Valence electrons are the electrons in the highest occupied energy level of the atom. • Valence electrons are the only electrons generally involved in bond formation.

15. Electron Configuration of Sodium • 1s2 2s2 2p6 3s1 • Which is the valence electron for Na? • Answer: 1s2 2s2 2p63s1

16. Na , 11 e

17. Na + , 10e

18. A Positive Ion (Cation): • An atom that has less electrons than protons due to the loss of one or more electrons from the stable atom state. • Therefore the ion contains a positive charge

19. Electron Dot Structure or Lewis Dot Diagram A notation showing the valence electrons surrounding the atomic symbol.

20. Elements within the same group have the same electron-dot structure.

21. A Negative Ion (Anion) • An atom that has more electrons than protons due to the gain of one or more electrons from the stable atom state. • Therefore the ion contains a negative charge

22. Chlorine Atom  Chlorine Ion

23. When Na, (Z= 11) loses its valence electron, what element does its configuration look like ? • Neon • Potassium • Beryllium • Sodium

24. A Stable Octet When the valence shell is full, the atom is stable, less likely to react. Example: Noble (Inert Gases) Kr

25. Note • Atoms tend to react in a way that would lead them to have a stable octet.

26. Equations for the Formation of Cations H. H+ + e- Li. Li+ + e- Mg: Mg2+ + 2e-

27. Equations for the Formation of Anions . .. : F : + e-:F -: ....

28. Ionic Compounds • Remember from the definition • Are made up of: • a metal and a nonmetal ion. • A metal and polyatomic ions. • Exception to this rule is hydrogen fluoride. This is determined by the significant difference in electronegativity between hydrogen and fluorine.

29. Example: • Which of the following compounds are ionic? • NaCl • CO2 • CO • KF • KNO3

30. Bonding • Elements that do not have a complete octet, tend to react. • When the elements react bonds are formed.

31. Types of Bonds • Ionic • Metallic • Covalent

32. Ionic Bonds • Bonds that are formed by transfer of electrons from one element to the other. • Each element (now an ion) will have a complete octet after the transfer of electrons.

33. The Ionic Bond • The electrical force of attraction between oppositely charged ions. F− Na+

34. Example: Formation of Lithium Fluoride . .. Li. +: F : Li+:F -: ....

35. Is an Ionic Compound Electrically Neutral or Charged?

36. Movie Clip • http://www.youtube.com/watch?v=Kj3o0XvhVqQ&NR=1

37. Chemical Formula • A representation of the kinds and number of atoms in a substance.

38. Formula Unit • A chemical formula that shows the lowest whole number ratio of the atoms (ions) in an ionic compound. • Example:KCl, Mg Cl2

39. The formula unit is used because ionic compounds have a lattice arrangement of ions. Ex: NaCl • Which ball represents the Na?

40. Ionic bonding workbook

41. Covalent Bonds

42. K F In an IONIC bond, electrons are lost or gained, resulting in the formation of IONS in ionic compounds.

43. K F

44. K F

45. K F

46. K F

47. K F

48. K F

49. _ + K F

50. _ + K F The compound potassium fluoride consists of potassium (K+) ions and fluoride (F-) ions