1. Putting Atoms Together (7.1)

2. ELEMENTS Consist of only one kind of atom
Cannot be broken down into a simpler type of matter by either physical or chemical means
Can exist as either atoms (eg. helium) or molecules (eg., nitrogen).
The atoms of the element helium, He
The molecules of the element nitrogen, N2

3. Molecules Can consist of 2 or more atoms of the
Same element (molecular element)
(eg. N2)
Different elements (molecular compound)
(eg. H2O)

4. Diatomic Elements
Diatomic elements are more stable when joined in a pair
There are seven elements that form molecules consisting of two atoms.
H2, N2, O2, F2, Cl2, Br2, I2
(H O Br F I N Cl)

5. The molecules of the compound water
COMPOUNDS
Consist of atoms of two or more different elements bonded together
Can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means)
Have properties that are different from the component elements
Always contain the same ratio of component atoms (constant composition).
The molecules of the compound water

6. Element, Compound, or Mixture?
Gas Liquid Solid A
Element B
Mixture
Compound C

7. Element, Compound, or Mixture?
Gas Liquid Solid D
Compound
Element E F
Mixture

8. Chemical Formula
is the notation used to indicate the type and number of atoms in a pure substance
Ex) Sugar: C12H22O11
How many: carbons ____
hydrogens ____
oxygens ____
Ex) Write the chemical formula for ammonia which has one nitrogen and three hydrogens _______ 12 22 11
NH3

9. The OCTET RULE & IONS electrons valence 8
The octet rule is a simple chemical theory that states that atoms gain, lose, or share _____________ so that they have eight electrons in their outer_________ shells, similar to the noble gases.
In simple terms, atoms are more stable when the outer shells of their atoms have _____ electrons.
hydrogen & helium only need to fill the 1st energy level (2 electrons) to become stable.
electrons
valence 8

10. When an atom loses or gains electrons (in order to have 8 valence electrons), it becomes charged and is known as an ______.
Atoms that gain electrons become _________ charged ions or _______.
Atoms that lose electrons become _________ charged ions or ________.
Ions have _____ outer shells and are ________.
ion
negatively
anions
positively
cations
full
stable

11. NOBLE GASES a) Describe the chemical reactivity of the NOBLE GASES.
very stable / not reactive
Draw Bohr-Rutherford diagrams for He, Ne, and Ar.
He Ne Ar
c) Why are the NOBLE GASES stable and unreactive? 2 10 18
  They all have full outer shells

12. ALKALI METALS
 2. a) Describe the chemical reactivity of the ALKALI METALS.
Very reactive
b) Draw Bohr-Rutherford diagrams for Li, Na, and K.
Li Na K 3 11 19

13. ALKALI METALS
 c) Why are the ALKALI METALS reactive (why are they not stable)?
  They do not have a full outer shell
It is easier for the atoms of the alkali metals to ___________electrons in order to get a full outer energy level.
How many electrons should the ALKALI METALS lose from their outer shell to be stable? _______
lose 1

14. ALKALI METALS
e) How many positive charges (protons) are there in Li+? ________
How many negative charges (electrons) are there in Li+? ________
What is the total charge on the stable Li+ ion? ________
f) How many positive charges (protons) are there in Na+? ________
How many negative charges (electrons) are there in Na+?________
What is the total charge on the stable Na+ ion? ________
g) What is the charge on ions of the ALKALI METALS? ________ 3+ 2- 1+
11+
10- 1+ 1+

15. HALOGENS 3. a) Describe the chemical reactivity of the HALOGENS.
Very reactive
b) Draw Bohr-Rutherford diagrams for F and Cl.
F Cl 9 17

16. HALOGENS
 c) Why are the HALOGENS reactive (why are they not stable)?
  They do not have a full outer shell
d) It is easier for the atoms of the halogens to ___________electrons in order to get a full outer energy level. How many electrons should the HALOGENS gain for their outer shell to be stable? _______
gain 1

17. HALOGENS
d) How many positive charges (protons) are there in F-? ________
How many negative charges (electrons) are there in F-? ________
What is the total charge on the stable F- ion? ________
f) How many positive charges (protons) are there in Cl-? ________
How many negative charges (electrons) are there in Cl-? ________
What is the total charge on the stable Cl- ion? ________
What is the charge on ions of the HALOGENS? ________ 9+
10- 1-
17+
18- 1- 1-

18. Let’s label the ionic charge trends on our Periodic Tables

19. Homework
pg 261 #1-9