1. I’ve gotta ask…..
Are You……
Thirsty for Chemistry?

2. Color Change Demonstration
Get a beaker……
No, not that Beaker.

3. Color Change Demonstration
“Water”
Water + Baking Soda
“Fruit Punch”
Phenolphthalein
(Think CSI)
“Milk”
Barium Chloride
Color Change Demonstration
Dichromate +
Hydrochloric acid
These are toxic, you cannot drink them!!

4. An Intro to Elements and the Periodic Table
It’s All in the Atom
An Intro to Elements and the Periodic Table

5. Elements
Robert Boyle ( ) gave the basis for modern definition of an element
“An element is a pure substance that cannot be chemically broken down into a simpler substance.
Every element has it’s own atomic structure, which we call an atom

6. Parts of an Atom An atom is made up of 3 types of particles.
1) The electron (e-)
Has a charge of -1
Has relatively no mass
Is found in an orbital/shell, around the nucleus of an atom

7. Parts of an Atom 2) The proton (p+) Has a charge of +1
Has a mass of 1 amu
Amu = Atomic Mass Unit
Is found in the nucleus of the atom

8. Parts of an Atom 3) the neutron (n) Has NO charge Has a mass of 1 amu
Is found in the nucleus of the atom

9. Bohr Diagram of the Atom
Niels Bohr was a Danish physicist.
He proposed a model of an atom where:
protons and neutrons are located in the centre of the atom (nucleus)
and the electrons move around the nucleus in orbits called shells

10. Bohr Diagrams Each shell can hold a specific number of electrons.
K-shell is the first shell and can hold 2 electrons
L-shell is the second shell and can hold 8 electrons
M-shell is the third shell and can hold 8 electrons
Remember: Neutral atoms always have the same number of electrons as protons (charges cancel)

11. Bohr Diagrams
E.g-a boron atom has 5 p+, 5 e-, and 6 n. Draw the Bohr diagram: + + + + +

12. Bohr Diagrams A beryillium atom has 4 p+, 4 e-, and 5n. Draw it: + + +

13. Bohr Diagram A phosphorus atom has 15 p+, 15 e-, and 16 n. Draw it:

14. Reading from the Periodic Table
Each element in the periodic table is represented by a symbol.
Every symbol has an upper case letter.
Some symbols have two letters.
The first is upper case
The second is lower case (e.g. Ca is calcium)

15. E.g. C is the symbol for carbon Cl is the symbol for chlorine
Cu is the symbol for copper

16. Atomic Number Is the number of protons that an atom has.
Each element has a unique atomic number.
Every element is arranged according to atomic number on the periodic table.
Atomic number = # of p+

17. Atomic Number
Is found in the top left-hand corner

18. Atomic Mass Is the mass of the atom in amu.
Since each proton has a mass of 1 amu, and each neutron has a mass of 1 amu, then the atomic mass is equal to the number of protons and neutrons.
Atomic mass =
# protons + # neutrons

19. Atomic Mass E.g. Nitrogen has 7 p+ and 7 n.
So, atomic mass = = 14 amu
Is found under the symbol.

20. On Your Periodic Table

21. Assignment
Use your periodic table to fill in the table on page 4. We’ll do a few together.

22. Symbol
Name
Atomic #
Atomic mass P+ e- n Li
Lithium 3 7 4 O
Oxygen 8 16 P
Phosphorus 15 31 F
Flourine 9 19 10 Br
bromine 35 80 45 Fe
iron 26 56 30 K
potassium 39 20 Bi
bismuth 83
210
127 Pb
lead 82
207
125