1. Chemistry C4 The Periodic Table

2. C4 Periodic Table
You will study atomic structure and learn how this underpins the chemical and physical properties of the elements and their positions in the periodic table. You will learn how atoms are held together by ionic, covalent and metallic bonding and how this influences their properties.
You will learn about the patterns and trends in the properties of the elements by studying the reactive metals in group 1, the non-metals in group 7, and the transition metals. You will find out why metals are so useful and how new technologies use superconductors.
Finally, you will learn how to detect dissolved ions and learn how water is treated to make it safe to drink.

3. Atomic Structure

4. Describe the structure of atoms.
C4a1 Objectives
Describe the structure of atoms.
Use ideas about atoms to compare elements and their isotopes.

5. Match symbols to elements
potassium W
hydrogen Cr As
boron
caesium Pt Pb Zr Hg
carbon
fluorine
lead Cs
chromium
polonium Fr
iron
Arsenic C
tungsten
mercury K Au B F
francium Fe
platinum
gold

6. Formulae of common compounds, fill in anything missing
water
NaOH
nitric acid
Carbon dioxide
CO2
SO2
methane
ammonium chloride
sodium sulfate
H2O
sodium hydroxide
HNO3
Sulfur dioxide
CH4
NH4Cl
Na2SO4

7. Key definitions
ATOM, ELEMENT, COMPOUND, MOLECULE
ATOM – smallest part of an element, takes part in chemical reactions
ELEMENT – a substance that consists of only one type of atom
COMPOUND – consists of two or more types of atom chemically combined together
MOLECULE – consists of two or more atoms bonded together

8. Atomic Structure Atoms are composed of 2 regions:
Nucleus: the center of the atom that contains the mass of the atom
Electron cloud: region that surrounds the nucleus that contains most of the space in the atom
Nucleus
Electron
Cloud

9. What’s in the Electron Cloud?
What’s in the Nucleus?
The nucleus is positively charged, it contains 2 particles:
Protons: positively charged particles
Neutrons: neutrally charged particles
What’s in the Electron Cloud?
The 3rd particle resides outside of the nucleus in the electron cloud
Electron: the particle with a negative charge

10. How do these particles interact?
Protons and neutrons live compacted in the tiny positively charged nucleus accounting for most of the mass of the atom
The negatively charged electrons are small and have a relatively small mass but occupy a large volume of space outside the nucleus

11. Shells around the outside of the atom
Particle
Where found in atom
Charge
Mass
proton
nucleus
+ 1 1
neutron
electron
Shells around the outside of the atom
- 1
0.0005
(almost zero)

12. HELIUM ATOM
Shell
proton N + - + N -
neutron
electron

13. An atom (summary) An atom has three parts: Proton = positive
Neutron = no charge
Electron = negative
The proton & neutron are found in the center of the atom, a place called the nucleus.
The electrons orbit the nucleus.

14. How do the particles balance each other?
In an atom:
No of protons = No of electrons
atoms are therefor neutral
e.g. If 20 protons are present in an element then 20 electrons are also present (Calcium)
The neutrons have no charge; they do not have to equal the number of protons or electrons

15. How do we know the number of particles in an atom?
Atomic number:
The number of protons in an atom (equal to the number
of electrons) – (small number)
Hydrogen’s atomic number is 1
So hydrogen has 1 proton
Carbon’s atomic number is 6
So carbon has 6 protons
The number of protons identifies the atom

16. How do we know the number of particles in an atom?
Mass number:
Total number of protons and neutrons in an
atom – (big number)
Carbon has a mass number of 12
Since it has 6 protons it must have 6 neutrons
Method to calculate neutrons
No of neutrons = mass No - atomic No

17. In an atom the number of electrons = number of protons
ATOMIC STRUCTURE He 4
Atomic mass (big number)
the number of protons and
neutrons in an atom 2
Atomic number (small number)
the number of protons in an atom
In an atom the number of electrons = number of protons

18. Helium has a mass No of 4 and an atomic No of 2
Number of particles?
Helium has a mass No of 4 and an atomic No of 2
protons = 2 (equal to atomic number)
neutrons= 2 (4-2)(mass No - atomic No)
electrons= 2 (equal to atomic number)

19. Determining the number of protons and neutrons
Li has mass number 7 and atomic number 3
Protons = 3 (same as atomic No)
Neutrons = 7-3 = 4 (mass No- atomic No)
Ne has mass number 20 and atomic number 10
Protons = 10
Neutrons = = 10

20. O Periodic Table Oxygen 16 8 Atomic Mass/Weight:
Number of protons + neutrons. 16 O
Element’s Symbol: An abbreviation for the element.
Oxygen
Elements Name 8
Atomic Number:
Number of protons and it is also the number of electrons in an atom of an element.

21. Atoms of the same element that have different numbers of neutrons are called isotopes.

22. C Mass No Atomic No Isotopes 12 6
Atoms of the same element with different mass numbers. (atomic numbers remain the same) 12 6 C
Mass No
Each isotope has a different number of neutrons.
Atomic No

23. Isotopes Carbon-12 and Carbon-14
Nucleus
Neutron
Proton +
Electrons
Nucleus
Nucleus
Neutron
Proton +
Carbon-12
Neutrons 6
Protons 6
Electrons 6
Electrons
The chemistry of each element is determined by its number of protons and electrons.
In a neutral atom, the number of electrons equals the number of protons.
Symbols for elements are derived directly from the element’s name.
Nuclei of atoms contain neutrons as well as protons.
The number of neutrons is not fixed for most elements, unlike protons.
Atoms that have the same number of protons, and hence the same atomic number, but different numbers of neutrons are called isotopes.
Carbon-14
Neutrons 8
Protons 6
Electrons 6
Nucleus

24. 6Li 7Li Neutrons 3 Protons 3 Neutrons 4 Electrons 3 Protons 3
Nucleus
Neutron
Proton
Nucleus
Neutron
Proton
Electrons +
Electrons +
Nucleus
Nucleus
Lithium-6
Lithium-7
Neutrons 3
Protons 3
Electrons 3
Neutrons 4
Protons 3
Electrons 3

25. Isotopes: Carbon
Natural samples of elements are often a mixture of isotopes. About 1% of natural carbon is carbon-13. C 13 6 1% C 12 6
99% 6 6 7
Protons
Electrons
Neutrons

26. H H H Isotopes: Hydrogen
Hydrogen exists as 3 isotopes although Hydrogen-1 makes up the vast majority of the naturally occurring element. H 1 H 2 1 H 3 1
Protons
Electrons
Neutrons
Hydrogen
Protons
Electrons
Neutrons
(Deuterium)
Protons
Electrons
Neutrons
(Tritium)

27. Cl Cl Isotopes: Chlorine
About 75% of natural chlorine is 35Cl the rest is 37Cl. Cl 35 17
75% Cl 37 17
25% 17
Protons
Electrons
Neutrons
Protons
Electrons
Neutrons 17 18 20

28. Atomic Number = Number of Protons
Using a periodic table and what you know about atomic number, mass, isotopes, and electrons, fill in the chart:
Element
Symbol
Atomic
Number
Mass
No of protons
No of neutrons
No of electrons 8
Potassium 39 Br 45 30 65
Atomic Number = Number of Protons
Number of Protons + Number of Neutrons = Atomic Mass
Atom (no charge) : Protons = Electrons

29. Using a periodic table and what you know about atomic number, mass, isotopes, and electrons, fill in the chart:
A N S W E R K E Y
Element
Symbol
Atomic
Number
Mass
No of protons
No of neutrons
No of electrons 8
Potassium 39 Br 45 30 65
Oxygen O 8 16 K 19 19 20 19
Bromine 35 80 35 35
Zinc Zn 30 35

30. Models of the Atom The End?
Atoms are tiny! A pinhead has a diameter of about 1mm. A line of 5 million million atoms could fit on a pinhead. Also the size of the nucleus in relationship to the whole atoms is very small. If the nucleus had a diameter equal to that of a pinhead, then the atom itself would have a diameter of 10 metres (the height of 5 men).
So small that we don’t really know what they look like Over the years there have been many theories of atomic structure. The one that you have probably learnt about at school is the one put forward by Bohr in He said that the atom consisted of a central nucleus (positive charge) which was surrounded by negatively charged electrons which orbited the nucleus in shells.
Clouds of mystery Bohr’s sharply defined electron shells have been superseded by fuzzy electron ‘clouds’ which can be seen with an electron microscope. It is now known that electrons behave as waves, as well as like particles. An electron is most likely to be found where the electron ‘cloud’ is dense. But there is always a definite, if small, chance of finding it closer to, or farther from, the nucleus.
Not just protons, neutrons and electrons Recently it has been discovered that protons and neutrons are made up of smaller particles called quarks and gluons.
Quark
Gluon
A picture of a neutron cut in half (remember we cannot really cut open a neutron and peer inside!)
A modern theory of atomic structure (David Bergman, 1990). This is a neon atom. The nucleus and the shells are visible but the electrons spin in a circular motion whilst orbiting the nucleus. The electrons exist as both waves and particles.
Nucleus
Electrons
Have we finally worked out the mystery of the atom or is there still more discoveries?
The End?

31. Distinguish formulas of elements and compounds.
C4a2 Objectives
Distinguish formulas of elements and compounds.
Use electronic structures to identify elements.
Explain how ideas about atomic structure developed.

32. HCl NaOH HNO3 CO2 H2SO4 CH4 NH4Cl C6H12O6
Name compounds and state how many atoms and elements are in each compound
HCl
NaOH
HNO3
CO2
H2SO4
CH4
NH4Cl
C6H12O6
2 elements, 2 atoms
3 elements, 3 atoms
3 elements, 5 atoms
2 elements, 3 atoms
3 elements, 7 atoms
2 elements, 5 atoms
3 elements, 6 atoms
3 elements, 24 atoms

33. How to Draw
Bohr Diagrams C

34. Bohr Diagrams Find your element on the periodic table.
Determine the number of electrons – it is the same as the atomic number.
This is how many electrons you will draw.

35. Bohr Diagrams Find out which period (row) your element is in.
Elements in the 1st period have one energy level.
Elements in the 2nd period have two energy levels, and so on.
Groups go down, elements in
the same group have the same
number of electrons in the
Outer shell
Periods go across they
indicate the number of shells
of electrons an atom has
Bohr Diagrams

36. Electronic Structure second shell a maximum of 8 electrons
Electrons are arranged in Energy Levels or Shells around the nucleus of an atom.
first shell a maximum of 2 electrons
second shell a maximum of 8 electrons
third shell a maximum of 8 electrons

37. How exactly are the particles arranged?
Bohr Model of the atom:
All of the protons and the neutrons in the nucleus
The 3rd shell can hold 8 e-
The 1st shell can hold 2 e-
The 4th shell can hold 8 e-
Outer shell
The 2nd shell can hold 8 e-

38. Li 7 Li 3 Lithium Protons = 3 Electrons = 3 2 in the 1st shell- Li - -
Electrons = 3
2 in the 1st shell
1 in the 2nd shell

39. Electronic structure and electronic configurationX 14 N
Nitrogen X X N X X 7 X X
configuration = 2, 5

40. ELECTRONIC CONFIGURATION
With electronic configuration elements are represented numerically by the number of electrons in their shells and number of shells. For example;
configuration = 2, 7
Fluorine 19
2 in 1st shell
7 in 2nd shell F
= 9 9

41. ELECTRONIC CONFIGURATION
Write the electronic configuration for the following elements; 40 23 16 Na O Ca a) b) c) 8 11 20
2,8,8,2
2,8,1
2,6 35 28 11 Cl Si B d) e) f) 5 17 14
2,8,7
2,8,4
2,3

42. Electronic structures
Draw the electronic structures for the following elements; X 16 35 X O Cl a) b) X 8 17 X X X X X X Cl X X X X X X X O X X X X X X X X X X

43. SUMMARY protons in the nucleus. The Atomic Mass of an atom = number of
The Atomic Number of an atom = number of
protons in the nucleus.
The Atomic Mass of an atom = number of
Protons + Neutrons in the nucleus.
The number of Protons = Number of
Electrons.
Electrons orbit the nucleus in shells.
Each shell can only carry a set number of
electrons.

44. C Practice Questions Draw a nucleus with the element symbol inside.
Carbon is in the 2nd period, so it has two energy levels, or shells.
Draw the shells around the nucleus. C

45. C Add the electrons. Carbon has 6 electrons.
The first shell can only hold 2 electrons. C

46. C Since you have 2 electrons already drawn, you need to add 4 more.
These go in the 2nd shell.
Add one at a time C

47. C Check your work. You should have 6 total electrons for Carbon.
Only two electrons can fit in the 1st shell.
The 2nd shell can hold up to 8 electrons.
The 3rd shell can hold 8 electrons. C

48. Have a go yourselves Try the following elements on your own: H He O AlNe K

49. Try the following elements on your own:
H – 1 electron He O Al Ne K H

50. He Try the following elements on your own: H He - 2 electrons O Al NeK He

51. Try the following elements on your own:
O - 8 electrons Al Ne K O

52. Al Try the following elements on your own: H He O Al - 13 electrons NeK Al

53. Ne Try the following elements on your own: H He O Al Ne - 10 electronsK Ne

54. K Try the following elements on your own: H He O Al Ne
K - 19 electrons K

55. Questions on electronic structures
What are the circles, electrons are drawn on known as?
What do the electronic structures of the group 1 metals have in common?
What do the electronic structures of the group 7 halogens have in common?
If an element has 4 electrons in its outer shell which group will it be in in the periodic table?
How many electrons will an element in group 6 have in its outer shell?

56. More Questions How many elements are there? What is an element?
How are the elements arranged in the periodic table?
Write the name and symbol of elements that are in the same group as potassium.
Write the name and symbol of the elements that are in the same period as sodium.
Which elements are in the compound sodium hydroxide NaOH?
Which elements and how many atoms of each element are in the compound Magnesium Sulfate, MgSO4?

57. Which of the following is not a sub-atomic particle?
Electron.
Proton.
Isotope.
Neutron.

58. The element Cobalt has a relative atomic mass of 59 and an atomic number of 27. Which of these is a true statement about each neutral cobalt atom?
It contains 59 neutrons.
It contains 27 electrons.
It contains 32 protons.
It contains equal numbers of neutrons and electrons.

59. contains more protons than neutrons.
The Periodic Table displays iron as shown below. This indicates that Fe atoms:
contain 56 neutrons.
contain 30 electrons.
contain 26 protons.
contains more protons than neutrons. 56 Fe 26

60. Which of the following is true: Both isotopes contain 35 protons.
Bromine consists of a mixture of two isotopes: Bromine-79 and Bromine-81
Which of the following is true:
Both isotopes contain 35 protons.
Bromine 79 contains 46 neutrons.
Bromine 81 contains 44 neutrons.
Bromine-81 is more reactive than bromine-79. 80 Br 35

61. Which answer best describes the shell arrangement of the electrons in a sodium atom?
2,8,1.
2,2,7.
2,8,8,3.
2,8,8,1. 23 Na 11

62. Which answer best describes the shell arrangement of the electrons in an oxygen atom?
2,8,6.
2,8,8.
2,8.
2,6. 16 O 8

63. Which of these elements will have electron shells that are completely full (i.e. not partially full)? 14 N 7 A 40 Ar 18 B 40 Ca 20 C 27 Al 13 D

64. Which answer best describes the shell arrangement of the electrons in an oxide ion O2-?
2,8,6.
2,8,8.
2,8.
2,6. 16 O 8