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.

Classification of Matter Biology 1

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

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

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

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

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.

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

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