Document 7891990

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Transcript Document 7891990

Introduction to Chemistry
What’s the MATTER?
• Matter is anything that has mass and
occupies space.
• Matter is made up of tiny particles
• Atoms are the ‘building blocks’ of all
• They are about one billionth of a meter
(very small)
• Protons are positively
charged and are
represented by the
symbol p+
• Protons are located in
the nucleus
• Neutrons have no
charge and are
represented by the
symbol n0
• Neutrons are also
located in the
• Electrons are located
outside of the nucleus
and are represented
by the symbol e• Electrons are located
in shells
• In an atom, there are the same number of
electrons as there are protons so there is
no charge.
The Periodic Table and Atoms
Using the Periodic Table….
• The Number of
protons is the ‘atomic
• The atomic weight is
a measure of the total
number of particles in
an atom’s nucleus.
Atomic Weight will always be larger
then Atomic Number!
Atomic Weight
• Atomic Weight = (Number of Protons) +
(Number of Neutrons)
* Atomic Weight is Atomic Mass
To determine the number of neutrons you
round mass to the nearest whole number.
For any element:
• Number of Protons = Atomic Number
• Number of Electrons = Number of Protons = Atomic
• Number of Neutrons = Atomic Weight – Atomic Number
How many valence electrons?
Valence ElectronsWhere all the ACTION is!
• Valence electrons are the number of electrons in the outermost shell
of an element.
• The number of valence electrons is the same for elements in the same
• REMEMBER: Groups are the Columns (Down)
Periods are the Rows (Across)
Example: Calcium (Ca) is in Group 2 and so is Radium (Ra).
Ca and Ra both have TWO valence electrons.
Chemical Reactions
• How Stuff Works Video- 9 minutes
Answers to Crosswords
Elements of the Periodic Table
1. Helium
4. Oxygen
5. Sodium
7. Neon
8. Silver
10. Calcium
13. Uranium
14. Chlorine
15. Arsenic
17. Gold
18. Carbon
19. Iron
2. Lead
3. Hydrogen
6. Mercury
7. Nitrogen
9. Sulphur
11. Aluminium
12. Copper
15. Argon
16. Silicon
Answers to Crosswords
• Periodic Table Assignment
1. Transitions
5. Periodic
7. Three
8. Massnumber
9. Noble Gases
10. Thirty two
13. Mendeleev
17. Thirty two
19. Gaseous
20. Bromine
21. Group
22. Two
2. Representative
3. Dobereiner
4. Germanium
6. Metals
11. Period
12. Halogens
14. Lithium
15. Hydrogen
16. Aqueous
18. IIA
20. Boron