1. Matter, Atoms and
The Periodic Table

2. Expected Learning To discover what I already know about Chemistry
To re-discover Elements and the Periodic Table
To learn more about an elements’ structure and placement within the table

3. Matter
Matter can be in almost any form

4. What's the Matter? Matter is all around us
We breathe it, drink it, sit on it
But what is it made of...?

5. Atoms
Atoms are the basic building blocks of matter that make up everyday objects
There are 90 naturally occurring kinds of atoms
(‘Mad Scientists’ in labs have been able to make about 25 more…)

7. Atoms Atoms are particles that make up matter
So small you cannot see them
Made of even smaller particles called;
Protons P+ have a positive charge
Neutrons N have no charge
Electrons E- have a negative charge
NB. Electrons 1800x smaller than P+ & N

8. Atomic Particles Protons have a positive charge; P+
Electrons have negative charge; E-
Opposites attract, so;
protons (P+) attract electrons (E-)
this keeps the atom together
Video: Basic Atom Structure

10. Atomic and Mass Numbers
Number of protons in an atom
is called its atomic number
Atoms electrically neutral
Atomic number;
Therefore, # of protons = # of electrons
Mass number = # of particles in the nucleus

11. Cl Mass & Atomic Number Mass number A 35 Symbol of element
So Chlorine (Cl) has;
17 protons & electrons
18 neutrons ( = 18 )

12. Elements Building blocks of all matter
Each element has only 1 type of atom
e.g. gold contains only gold atoms
111 basic atoms currently known
Each element has it's own symbol
E.g. H = Hydrogen, Ca = Calcium, Au = Gold

14. Compounds Molecules & Lattices
Atoms not always by themselves
More than one joined atom is a molecule
More than one type of atom together is called a compound

15. Mixtures Made of different elements or compounds
E.g. Salt water, cup of coffee, soft drink, blood

16. Periodic Table Certain elements have similar features;
Physical properties
Colour, melting and boiling point, density and hardness
Like they are in the same 'family'
Chemical properties
Similar but not identical

17. Features of the Periodic Table
80% of elements are metals
Smaller set non-metals
Some in between are metalloids

18. Features of the Periodic Table
Most reactive are bottom left
Most reactive non-metals top right
Does not include right column of unreactive gases
These have full outer electron shells & are stable

19. Features of the Periodic Table
Most reactive elements are bottom left
Most reactive non-metals top right
Excludes right column of unreactive gases
These have full outer electron shells & are stable

20. Periods, Groups & Electrons
Period number = number of electrons shells
Horizontal ( left-to-right ) rows

21. Electron Shells
Electrons are found around atoms in shells (also called energy levels)
Each shell (or energy level) can only hold a set number of electrons
1st shell = nd shell = rd shell =

22. Electron Configuration
Is the arrangement of electrons
Silicon (Si) has atomic #14
So 14 electrons, 14 protons
First shell has 2 electrons
Second shell has 8 electrons
Third shell has 4 electrons
So Silicon’s electron shells are (2, 8, 4)

23. Elements in the same group have the same number of electrons in their outer shell
And have similar chemical properties
Moving down a group, adds more shells

24. Same Group
Group 1 = one electron on outer shell

25. Atoms that React & Don't React
Group VIII (“8”) Elements
Group VIII contains noble or inert gases
These elements have full outer shells
Very stable and rarely react

26. Ions Atoms normally neutral in charge
Because protons (P+) = electrons (E-)
If this balance is changed, then an atom becomes charged and is called an ion
This happens when electrons move from one atom to another atom

27. Ions If an atom loses an electron, it becomes positively charged
Because now more protons (+) than electrons (-)
So now; 10x electrons
11x protons
Electron lost

28. Ions If an atom gains an electron, it becomes negatively charged
Because more electrons (E-) than protons (P+)
So now; 18x electron
17x proton
Electron gained

29. Ions
If a sodium (‘Na’) atom meets a chlorine atom, the sodium loses it's outer shell electron
Now it has more protons than electrons
More protons = positively charged

30. Ions – Opposites Attract
Chlorine gains the electron from sodium
Both atoms now more stable as outer electron shells are full

31. Sodium Chloride
The ions are now held together by opposite charge = ionic bonding (video)
Many can join to form a crystal
Like table salt

32. What is a “metal”? Metals have certain properties;
Conduct heat and electricity
Shine when cut / polished = lustre
Malleable = change shape with force
Ductile = can be stretched in long thin wires
Solid at room temperature
(Mercury (Hg) an exception) *
High density (i.e. can sink in water)
E.g. Silver (Ag), Gold (Au)

34. What is a “Non-Metal”?
Mostly poor conductors or are insulators (do not conduct electricity at all)
Low melting and boiling points
Usually liquids and gases at room temperature
Any solids usually brittle (i.e. break easily)
Usually dull with no lustre
E.g. Oxygen (O) and Nitrogen (N)

36. Electronegativity
The attracting power of electrons is called electronegativity
Non-metals are more greedy for electrons than metals
So non-metals have higher electronegativity
They gain electrons from metals in chemical reactions
Metals become positive ions
Now have more protons (P+)that electrons (E-)
Non-metals become negative ions

37. Names of Non-Metals Ions
Names of non-metal atoms change name when they become ions
Non-Metal Atom
Name of Atom
Ion Formed
Name of Ion F
Flourine F-
Flouride Cl
Chlorine
Cl-
Chloride Br
Bromine
Br-
Bromide O
Oxygen
O2-
Oxide N
Nitrogen
N3-
Nitride

38. Special Case: Hydrogen & Helium
Can gain an electron to become an ion (H-)
Or give away an electron to become ion (H+)
Helium
Has full shell so could be in Group 2
But has similar properties to noble gases
So placed in Group 8

39. Metalloids Most properties like non-metals
But importantly can conduct electricity (like metals)

40. Families of Importance
Group VIII = noble gases
Colourless gases
Occur naturally
Very stable (i.e. full outer shell)
Helium (He) safe and light
E.g. party balloons

41. Families of Importance
Group VII = the halogens
Form ions with a charge of -1
i.e. gain an electron
Never pure in nature
Found in salts (e.g. NaCl)
Coloured poisonous vapours
Form diatomic molecules
F2, Cl2, Br2, I2

42. Group VII - Halogens

43. Group I – Alkali Metals Form +1 ions Reactive Metallic properties
Not found in pure form
Metallic properties
Extreme chemical
behaviour

44. Group II – Alkali Earths
Act in a similar way
to Group I but less
reactive

45. Atom vs Ion

46. For example, this is the electron configuration table for gold:
2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f14
5s2 5p6 5d10
6s1