The Periodic Table of the Elements

1. The Periodic Table of the Elements

2. History of the Periodic Table • (1800) Chemical substances elements compounds

3. History of the Periodic Table • (1800) Chemical substances elements compounds • Doböreiner showed that combining weight of strontium was halfway between calcium and barium (1817) • trends in elements oxygen, sulphur, selenium and tellurium

4. History of the Periodic Table • (1800) Chemical substances elements compounds • Doböreiner showed that combining weight of strontium was halfway between calcium and barium (1817) • trends in elements oxygen, sulphur, selenium and tellurium • de Chancourois (1862) arranged the elements in a helical curve, each turn differing by 16 in atomic weight • Newlands (1863) organised elements into groups of eight

5. History of the Periodic Table • Newlands (1863) organised elements into groups of eight H Li Be B C N O 1 2 3 4 5 6 7 F Na Mg Al Si P S 8 9 10 11 12 13 14

6. Mendeleev (1869) proposed an atomic table based on the relationship between the atomic weights and the physical and chemical properties of the elements

7. Mendeleev (1869) proposed an atomic table based on the relationship between the atomic weights and the physical and chemical properties of the elements • Mendeleev predicted the existence of 6 elements (and their properties) which had not yet been discovered- all six were discovered and their properties were similar to those predicted

8. Mendeleev (1869) proposed an atomic table based on the relationship between the atomic weights and the physical and chemical properties of the elements • Mendeleev predicted the existence of 6 elements (and their properties) which had not yet been discovered- all six were discovered and their properties were similar to those predicted Property Eka-silicon Germanium molar mass/g mol-1 72 72.59 density/ g cm-3 5.5 5.32 melting point/ ºC high 937

9. Mendeleev (1869) proposed an atomic table based on the relationship between the atomic weights and the physical and chemical properties of the elements • Mendeleev predicted the existence of 6 elements (and their properties) which had not yet been discovered- all six were discovered and their properties were similar to those predicted Property Eka-silicon Germanium molar mass/g mol-1 72 72.59 density/ g cm-3 5.5 5.32 melting point/ ºC high 937 • Atomic number replaced by atomic mass

10. The properties of an element depend upon the electronic • configuration of the atom • The Periodic Table (P.T.) • A system where elements of similar e- configuration • (and hence chemistry) are grouped together

11. The properties of an element depend upon the electronic • configuration of the atom • The Periodic Table (P.T.) • A system where elements of similar e- configuration • (and hence chemistry) are grouped together • Structure of P.T. • arrange rows (periods) in order of filling of electronic • orbitals (1 row per principle quantum level or "shell")

12. The properties of an element depend upon the electronic • configuration of the atom • The Periodic Table (P.T.) • A system where elements of similar e- configuration • (and hence chemistry) are grouped together • Structure of P.T. • arrange rows (periods) in order of filling of electronic • orbitals (1 row per principle quantum level or "shell") • arrange columns (groups) so that elements with the • same outer e- configuration are above one another

13. Periodic Table of Mendeleev and Mayer (1872) • 1s • 2s 2p • 3s 3p • 4s 3d 4p • 5s 4d 5p • 6s 4f 5d 6p • 7s 5f 6d 7p • s f d p • 'blocks'

14. Structure of P.T. arrange rows (periods) in order of filling of electronic orbitals (1 row per principle quantum level or "shell") arrange columns (groups) so that elements with the same outer e- configuration are above one another

15. Trends in the Periodic Table • Atomic radius: • decreases across periods, increases down groups • increasing nuclear charge • increased screening of outer e- 's

16. Atomic radii: electron clouds are diffuse atoms - defined radius 2 r 2 r Cl2 r = 99 pm C-C r = 77 pm C-Cl d predicted to be 176 pm, experimentally d = 178 pm

17. Trends in the Periodic Table • Cu Cu+ + e- 745 kJ mol-1 • First ionisation energy: • increases across periods, decreases down groups • increasing nuclear charge • increasing atomic size • Ionisation energy is much higher if e- is from closed shell

18. Trends in the Periodic Table • Electronegativity: • Measure of the attraction of an atom for electrons in a bond • increases across periods, decreases down groups • increasing nuclear charge increasing atomic size • & less efficient screening

19. Characteristics of metals and nonmetals Metals Nonmetals Physical properties good conductors of electricity poor conductors of electricity ductile not ductile malleable, lustrous not malleable typically: solid solid, liquid or gas high melting point low melting point good conductors of heat poor conductors of heat

20. Characteristics of metals and nonmetals Metals Nonmetals Physical properties good conductors of electricity poor conductors of electricity ductile not ductile malleable, lustrous not malleable typically: solid solid, liquid or gas high melting point low melting point good conductors of heat poor conductors of heat Chemical properties react with acids do not react with acids form basic oxides form acidic oxides (react with acids) (react with bases) form cations form anions form ionic halides form covalent halides

21. Properties of the Elements s block • metallic • reactive-elements have low ionisation energies (e- can be lost readily) - e.g. Na reacts violently with water

22. Properties of the Elements s block • metallic • reactive-elements have low ionisation energies (e- can be lost readily) - e.g. Na reacts violently with water p block • metals, metalloids and non-metals • not as reactive as s block, e.g. Sn used in alloys • moving across a period, elements have greater tendency to form molecular compounds with each other and to react with metals to form anions, e.g., Cl2 and NaCl

23. Properties of the Elements s block • metallic • reactive-elements have low ionisation energies (e- can be lost readily) - e.g. Na reacts violently with water p block • metals, metalloids and non-metals • not as reactive as s block, e.g. Sn used in alloys • moving across a period, elements have greater tendency to form molecular compounds with each other and to react with metals to form anions, e.g., Cl2 and NaCl d block • transition elements • metals • can have variety of oxidation states, e.g. Cu+, Cu2+

24. The Periodic Table - Summary • Structure & use of Periodic Table • Trends in elemental properties • - atomic radius • - first ionisation potential • - electronegativity

25. When 3 cm3 of ethylene and 12 cm3 of hydrogen are mixed under appropriate conditions, they react to form ethane: C2H4(g) + H2(g) C2H6(g) What is the final volume of the reaction mixture?

26. When 3 cm3 of ethylene and 12 cm3 of hydrogen are mixed under appropriate conditions, they react to form ethane: C2H4(g) + H2(g) C2H6(g) What is the final volume of the reaction mixture? Gay Lussac 3 cm3 of ethylene reacts with 3 cm3 of hydrogen to give 3 cm3 of ethane

27. When 3 cm3 of ethylene and 12 cm3 of hydrogen are mixed under appropriate conditions, they react to form ethane: C2H4(g) + H2(g) C2H6(g) What is the final volume of the reaction mixture? Gay Lussac 3 cm3 of ethylene reacts with 3 cm3 of hydrogen to give 3 cm3 of ethane 9 cm3 of hydrogen remain so the final volume = 12 cm3

28. In the reaction Cu + 2 HNO3 Cu(NO3)2 + H2(g) what volume of 10 M HNO3 is required to produce 11.2 dm3 of hydrogen?

29. In the reaction Cu + 2 HNO3 Cu(NO3)2 + H2(g) what volume of 10 M HNO3 is required to produce 11.2 dm3 of hydrogen? 11.2 dm3 11.2/22.4 = 0.5 moles of H2

30. In the reaction Cu + 2 HNO3 Cu(NO3)2 + H2(g) what volume of 10 M HNO3 is required to produce 11.2 dm3 of hydrogen? 11.2 dm3 11.2/22.4 = 0.5 moles of H2 2 molecules of HNO3 produce 1 molecule of H2 2 moles of HNO3 produce 1 mole of H2 => 1 mole of HNO3 is required

31. In the reaction Cu + 2 HNO3 Cu(NO3)2 + H2(g) what volume of 10 M HNO3 is required to produce 11.2 dm3 of hydrogen? 11.2 dm3 11.2/22.4 = 0.5 moles of H2 2 molecules of HNO3 produce 1 molecule of H2 2 moles of HNO3 produce 1 mole of H2 => 1 mole of HNO3 is required 10 M HNO3  10 moles HNO3 per Litre 10 moles in 1 L => need 1/10 or 100 ml of HNO3

32. What mass of solid sodium hydroxide, of 97% purity by weight, would be required to prepare 0.5 dm3 of a 0.46 M solution?

33. What mass of solid sodium hydroxide, of 97% purity by weight, would be required to prepare 0.5 dm3 of a 0.46 M solution? Molar mass of NaOH = 23 + 16 + 1 = 40 g 0.5 dm3 of 1 M solution would require 0.5 moles

34. What mass of solid sodium hydroxide, of 97% purity by weight, would be required to prepare 0.5 dm3 of a 0.46 M solution? Molar mass of NaOH = 23 + 16 + 1 = 40 g 0.5 dm3 of 1 M solution would require 0.5 moles 0.5 dm3 of 0.46 M solution would require 0.5 x 0.46 moles

35. What mass of solid sodium hydroxide, of 97% purity by weight, would be required to prepare 0.5 dm3 of a 0.46 M solution? Molar mass of NaOH = 23 + 16 + 1 = 40 g 0.5 dm3 of 1 M solution would require 0.5 moles 0.5 dm3 of 0.46 M solution would require 0.5 x 0.46 moles 0.5 dm3 of 0.46 M solution would require 0.5 x 0.46 x 40 g

36. What mass of solid sodium hydroxide, of 97% purity by weight, would be required to prepare 0.5 dm3 of a 0.46 M solution? Molar mass of NaOH = 23 + 16 + 1 = 40 g 0.5 dm3 of 1 M solution would require 0.5 moles 0.5 dm3 of 0.46 M solution would require 0.5 x 0.46 moles 0.5 dm3 of 0.46 M solution would require 0.5 x 0.46 x 40 g 0.5 dm3 of 0.46 M solution (97 % purity) would require 0.5 x 0.46 x 40/0.97 g = 9.48 g

37. Combustion of 1g of menthol, the flavouring agent obtained in peppermint oil, yielded 1.161 g of H2O and 2.818 g of CO2. Given that menthol contains carbon, hydrogen and oxygen, what is its empirical formula?

38. Combustion of 1g of menthol, the flavouring agent obtained in peppermint oil, yielded 1.161 g of H2O and 2.818 g of CO2. Given that menthol contains carbon, hydrogen and oxygen, what is its empirical formula? Hydrogen: 1.161 g of H2O  1.161/(2 + 16) = 0.0645 moles of water => 0.0645 x 2 = 0.129 moles of hydrogen

39. Combustion of 1g of menthol, the flavouring agent obtained in peppermint oil, yielded 1.161 g of H2O and 2.818 g of CO2. Given that menthol contains carbon, hydrogen and oxygen, what is its empirical formula? Hydrogen: 1.161 g of H2O  1.161/(2 + 16) = 0.0645 moles of water => 0.0645 x 2 = 0.129 moles of hydrogen Carbon: 2.818 g of CO2 2.818/(12 + 2 x 16) = 0.0640 moles of CO2 => 0.0640 of moles of carbon

40. Oxygen: 1.0 - 0.13 - 0.768 g = 0.102 g of oxygen  0.102/16

41. Oxygen: 1.0 - 0.13 - 0.768 g = 0.102 g of oxygen  0.102/16 = 0.064 moles of oxygen 0.129 H : 0.064 C : 0.064 O

42. Oxygen: 1.0 - 0.13 - 0.768 g = 0.102 g of oxygen  0.102/16 = 0.064 moles of oxygen 0.129 H : 0.064 C : 0.064 O 2 H : 1 C : 1 O Empirical formula: CH2O

43. The concentration of glucose (C6H12O6) in blood is normally 90 mg per 100 ml. What is the molarity of glucose?

44. The concentration of glucose (C6H12O6) in blood is normally 90 mg per 100 ml. What is the molarity of glucose? Molar mass of glucose is 6 x 12 + 12 x 1.008 + 6 x 16 = 180.1 g mol-1

45. The concentration of glucose (C6H12O6) in blood is normally 90 mg per 100 ml. What is the molarity of glucose? Molar mass of glucose is 6 x 12 + 12 x 1.008 + 6 x 16 = 180.1 g mol-1 90 mg = 9 x 10-2 g => molarity = 9 x 10-2 g 180.1 x 0.1 g mol-1 dm3 = 5 mM

46. What is the oxidation state of arsenic in H2AsO4-?

47. What is the oxidation state of arsenic in H2AsO4-? O.S. of H = 1 O.S. of O = -2 sum of oxidation states = -1

48. What is the oxidation state of arsenic in H2AsO4-? O.S. of H = 1 O.S. of O = -2 sum of oxidation states = -1 = 2 (1) + x + 4(-2) = x - 6 => x = +5