1. S2 Science
Atomic Structure

2. LEARNING INTENTION
We are learning about atomic structure

3. SUCCESS CRITERIA
I can state that all matter is made up of atoms and that a substance that is made up of the same kind of atoms is an element
I can describe the basic structure of an atom and state the location and charge of the proton, electron and neutron within the atom structure
I can state the relative masses of the proton, neutron and electron.
I can explain what is meant by atomic number and state that all elements are arranged in order of increasing atomic number in the Periodic Table

4. SUCCESS CRITERIA
I can state that the mass number is the number of protons plus the number of neutrons present in an atom
I can use nuclide notation to present information about atomic and mass numbers of atoms
I can explain what is meant by the term isotope
I can state that the electrons of an atom are arranged in energy levels
I can state that an atom is neutral and explain why

5. Modern Atomic Theory
All elements are made of identical tiny particles called atoms.
At first scientists thought atoms were solid spheres.

6. Modern Atomic Theory
All elements are made of identical tiny particles called atoms.
At first scientists thought atoms were solid spheres.
We now know that this is not true. Atoms are made up of smaller particles called protons, electrons and neutrons.

7. Modern Atomic Theory The protons and neutrons are in the nucleus.
The electrons orbit around the nucleus

8. Use Standard Chemistry p23
Modern Atomic Theory
Particle
Charge
Mass
(amu)
Found where?
Proton
Neutron
electron
Use Standard Chemistry p23

9. Use Standard Chemistry p23
Modern Atomic Theory
Particle
Charge
Mass
(amu)
Found where?
Proton +1 1
nucleus
Neutron
electron
Use Standard Chemistry p23

10. Use Standard Chemistry p23
Modern Atomic Theory
Particle
Charge
Mass
(amu)
Found where?
Proton +1 1
nucleus
Neutron
electron
Use Standard Chemistry p23

11. Use Standard Chemistry p23
Modern Atomic Theory
Particle
Charge
Mass
(amu)
Found where?
Proton +1 1
nucleus
Neutron
electron -1
1/1840
Outside
Use Standard Chemistry p23

12. Modern Atomic Theory The ATOMIC NUMBER is equal to The MASS NUMBER is
The number of electrons in an atom is equal to
The number of neutrons in an atom is equal to

13. Modern Atomic Theory
The ATOMIC NUMBER is equal to the number of protons in an atom
The MASS NUMBER is
The number of electrons in an atom is equal to
The number of neutrons in an atom is equal to

14. Modern Atomic Theory
The ATOMIC NUMBER is equal to the number of protons in an atom
The MASS NUMBER is the number of protons plus the number of neutrons
The number of electrons in an atom is equal to
The number of neutrons in an atom is equal to

15. Modern Atomic Theory
The ATOMIC NUMBER is equal to the number of protons in an atom
The MASS NUMBER is the number of protons plus the number of neutrons
The number of electrons in an atom is equal to the number of protons
The number of neutrons in an atom is equal to

16. Modern Atomic Theory
The ATOMIC NUMBER is equal to the number of protons in an atom
The MASS NUMBER is the number of protons plus the number of neutrons
The number of electrons in an atom is equal to the number of protons
The number of neutrons in an atom is equal to the mass number – the number of protons

17. Modern Atomic Theory Cl
Nuclide notation can be used to show the number of protons, neutrons and electrons in an atom eg
Mass number 37 Cl 17
Atomic number

18. Modern Atomic Theory Atomic number = number of protons
Number of protons = number of electrons
Mass number = protons + neutrons
Number of neutrons = mass number – atomic number

19. Modern Atomic Theory Cl Number of protons = Number of electrons =
Number of neutrons = 37 Cl 17

20. Modern Atomic Theory Cl Number of protons = 17 Number of electrons =
Number of neutrons = 37 Cl 17

21. Modern Atomic Theory Cl Number of protons = 17
Number of electrons = 17
Number of neutrons = 37 Cl 17

22. Modern Atomic Theory Cl Number of protons = 17
Number of electrons = 17
Number of neutrons = 20 37 Cl 17

23. Modern Atomic Theory 19 40 9 10 Element Atomic number Mass protons
electrons
neutrons 19 40 9 10 24 Mg 12 80 Br 35

24. Modern Atomic Theory 12 19 40 9 10 Element Atomic number Mass protons
electrons
neutrons 12 19 40 9 10 24 Mg 12 80 Br 35

25. Modern Atomic Theory 12 19 40 9 10 Element Atomic number Mass protons
electrons
neutrons 12 19 40 9 10 24 Mg 12 80 Br 35

26. Modern Atomic Theory 12 19 40 9 10 Element Atomic number Mass protons
electrons
neutrons 12 19 40 9 10 24 Mg 12 80 Br 35

27. Modern Atomic Theory 12 24 19 40 9 10 Element Atomic number Mass
protons
electrons
neutrons 12 24 19 40 9 10 24 Mg 12 80 Br 35

28. Modern Atomic Theory 12 24 19 40 9 10 Element Atomic number Mass
protons
electrons
neutrons 12 24 19 40 9 10 24 Mg 12 80 Br 35

29. Modern Atomic Theory 12 24 35 80 45 19 40 9 10 Element Atomic number
Mass
protons
electrons
neutrons 12 24 35 80 45 19 40 9 10 24 Mg 12 80 Br 35

30. Modern Atomic Theory 12 24 35 80 45 19 40 9 10 Element Atomic number
Mass
protons
electrons
neutrons 12 24 35 80 45 19 40 9 10 24 Mg 12 80 Br 35 K

31. Modern Atomic Theory 12 24 35 80 45 19 40 9 10 Element Atomic number
Mass
protons
electrons
neutrons 12 24 35 80 45 19 40 9 10 24 Mg 12 80 Br 35 40 K 19

32. Modern Atomic Theory 12 24 35 80 45 19 40 21 9 10 Element Atomic
number
Mass
protons
electrons
neutrons 12 24 35 80 45 19 40 21 9 10 24 Mg 12 80 Br 35 40 K 19

33. Modern Atomic Theory 12 24 35 80 45 19 40 21 9 10 Element Atomic
number
Mass
protons
electrons
neutrons 12 24 35 80 45 19 40 21 9 10 24 Mg 12 80 Br 35 40 K 19 F 9

34. Modern Atomic Theory 12 24 35 80 45 19 40 21 9 10 Element Atomic
number
Mass
protons
electrons
neutrons 12 24 35 80 45 19 40 21 9 10 24 Mg 12 80 Br 35 40 K 19 19 F 9

35. Arranging Electrons Target Model
The target model of an atom is a picture that shows clearly how the electrons in an atom are arranged in separate energy levels.

36. Target Model Example An atom with 15 electrons
Only 2 electrons can fit into the first energy level.
15+

37. Target Model Only 2 electrons can fit into the first energy level.
8 electrons fit into the next shell
15+

38. Target Model Only 2 electrons can fit into the first energy level.
8 electrons fit into the next shell
The five remaining electrons fit into the third shell.
15+

39. Electron Arrangements
An electron arrangement is a sequence of numbers that says how many electrons are in each energy level of an atom starting from the inside and working outwards.
15+
2,8,5

40. Electron ArrangementsLi Na F Si

41. Electron Arrangements
Li 2,1 Na F Si

42. Electron Arrangements
Li 2,1
Na 2,8,1 F Si

43. Electron Arrangements
Li 2,1
Na 2,8,1
F 2,7 Si

44. Electron Arrangements
Li 2,1
Na 2,8,1
F 2,7
Si 2,8,4
The number of electrons in the outer shell is the same as the group number.

45. Target Pictures
A target picture of an atom shows clearly how the electrons are arranged in the separate energy levels.

46. Drawing Target Pictures
Potassium

47. Drawing Target Pictures
Potassium
19+
2,8,8,1

48. Drawing Target Pictures
Sulphur

49. Drawing Target Pictures
Sulphur
The first 4 electrons in the shell are unpaired.
Any further electrons form pairs.
16+
2,8,6

50. Isotopes
Isotopes are atoms of the same element but with a different mass number.
Isotope
protons
electrons
neutrons Cu 63 Cu 29 65 29

51. Isotopes
Isotopes are atoms of the same element but with a different mass number.
Isotope
protons
electrons
neutrons 29 Cu 63 Cu 29 65 29

52. Isotopes
Isotopes are atoms of the same element but with a different mass number.
Isotope
protons
electrons
neutrons 29 Cu 63 Cu 29 65 29

53. Isotopes
Isotopes are atoms of the same element but with a different mass number.
Isotope
protons
electrons
neutrons 29 34 Cu 63 Cu 29 65 29

54. Isotopes
Isotopes are atoms of the same element but with a different mass number.
Isotope
protons
electrons
neutrons 29 34 Cu 36 63 Cu 29 65 29

55. Isotopes
They have different mass numbers because they have a different number of neutrons.

56. Isotopes
They have different mass numbers because they have a different number of neutrons.

57. Isotopes
In the data book, the mass number of each element is given as an average of all the isotopes.

58. Isotopes
In the data book, the mass number of each element is given as an average of all the isotopes.
This is called the relative atomic mass

59. Isotopes
In the data book, the mass number of each element is given as an average of all the isotopes.
This is called the relative atomic mass
It does not need to be a whole number

60. eg chlorine
Chlorine has 2 isotopes
Cl Cl 35 37 17 17

61. eg chlorine Chlorine has 2 isotopes Cl Cl p =17 e =17 n =20 p =1735 37 17 17

62. eg chlorine Chlorine has 2 isotopes Cl Cl 75% 25% p =17 e =17 n =20
75% 25%
p =17
e =17
n =20
p =17
e =17
n =18 35 37 17 17

63. eg chlorine Chlorine has 2 isotopes Cl Cl 75% 25%
75% 25%
Weighted average (75 X 35) + (25 X 37) / 100
Relative atomic mass 35.5
p =17
e =17
n =20
p =17
e =17
n =18 35 37 17 17