1. 6.6 – NOTES Symbols, Formulas, and Equations

2. B.4 Particulate View of Water
Particulate level: the level of atoms and molecules
Atoms
Building blocks of matter
Made up of protons and neutrons in the nucleus, and electrons in the electron cloud
Elements
One single type of atom – gold (Au), Oxygen (O)
Compound
Two or more elements bonded together
Written using formulas – H2O, CuSO4

3. Elements and compounds are considered to be substances
Substances have uniform and fixed composition and properties separate from the elements themselves
Smallest unit of a substance is a molecule
Molecules are held together by bonds, which are either covalent or ionic

4. B.6 Symbols, Formulas, and Equations
Chemists use an international language to convey information so everyone can understand it
The language of chemistry is made of symbols, formulas, and equations
Chemical symbols- letters
Each element has a unique symbol of 1 or 2 letters;
some based on old Latin name and not related to what they are known by today
1st letter – capital
2nd letter – lower case
Lead Pb plumbum
Tin Sn Stannum
Potassium K Katrium
Sodium Na Natrium

5. Chemical formulas- words
Make use of subscripts
Number written below line H2O
Tell how many atoms of each kind are present in 1 unit of the substance
Counting atoms in a formula
How many atoms of each element are present in the following compounds?
Al2(SO4)3 FeCl3
Al – 2 Fe – 1
S – 3 Cl – 3
O - 12

6. Chemical equations- sentences 2 H2 + O2  2H2O
Summarize details of chemical reactions
Reactants- what you start with; left side of the arrow
Products- what you finish with; right side of the arrow

7. Diatomic molecules Br2 I2 N2 Cl2 H2 O2 F2 “Brinclhof”
Made up of 2 atoms of the same element
Never found as single atoms in nature when the element is by itself.
The diatomic elements are
Br2 I2 N2 Cl2 H2 O2 F2
“Brinclhof”

8. B.8 the Electrical Nature of Matter
Like charges repel; opposite charges attract
Atoms are made up of three components that are charged
+ protons (p+)
 – electron (e-)
0 (neutral) – neutrons (n0)
The attraction between protons and electrons is what holds atoms together in chemical bonds
Nucleus – center of atom; holds protons and neutrons – positive charge
Electron cloud – region around nucleus where electrons are negative charge
Atoms are neutral – # protons = # electrons