1. Daily Science
What’s the rule for how many electrons can fit in each orbital 1-3?
What does valence mean?
Draw a Bohr model for Nitrogen. Remember to determine p+, n0, and e- first.

2. Classification of Matter
Biology 1

3. Three Classifications of Matter
Atom- the most basic unit of matter and the smallest particle of an element.
Examples of Atoms: Na C Fe

4. Three Classifications of Matter
Molecule – is composed of two or more atoms bonded together. A molecule is the smallest unit of a compound.
Examples of Molecules:
H2, N2, O2- these are actually diatomic elements. They are elements because they consist of a single type of atom.
H2O
NH3

5. Three Classifications of Matter
Compound – substance consisting of two or more different elements combined in a fixed ratio. A compound is also a molecule.
The physical and chemical properties of compounds are very different than those of the elements that form it.
Examples of compounds-
HCl
NaCl

6. Question
Can you give me an example of a compound that has very different properties than the elements that compose it?
Examples: oxygen and hydrogen separate are gases together they make water, chlorine is a poisonous gas but combined with sodium gives us table salt

7. Reading Chemical Formulas
Molecules and compounds are written in chemical formulas.
element symbol
H2O
subscript
The element symbol tells you which elements are found in the molecule/compound.
The subscript tells you how many of a particular atom are in the molecule/compound.

8. Chemical Formula Baking Soda and Vinegar Reaction
CH3COOH + NaHCO3 H2O + NaOCOCH3 + CO2
Reactants
Yields
Products

9. Reading Chemical Formulas
What atoms are present?
Nitrogen
How many atoms?
Nitrogen = 2
NaOH
Sodium, Oxygen, Hydrogen
How many of each atom?
Sodium = 1, Oxygen = 1, Hydrogen = 1
AgCl3Cu2
Silver, Chlorine, Copper
Silver = 1, Chlorine = 3, Copper = 2