Lesson 3: Periodic Table

Atoms An atom is the smallest particle of an element that has all the properties of that element The three parts of an atom are: Protons, Neutrons Electrons Protons/Neutrons are found in the nucleus while electrons are found in an electron cloud outside the nucleus. Valence electrons are in the outermost energy and are responsible for bonding

Groups and Periods Groups or families (vertical column) of elements are listed by increasing atomic number and they have similar chemical properties. Ex. calcium and magnesium would have similar properties.   Horizontal rows are called periods. Group 1: Alkali Metals are the most reactive metals Group 17: Halogens are the most reactive nonmetals. These two groups are most likely to form bonds together. Group 18: Noble Gases: are resistant to bonding and largely unreactive. This is because they have 8 valence electrons making them stable atoms.

Metals and Nonmetals Properties of Metals Properties of Nonmetals Metals are electron LOSERS Located on the left side of the stair step. Bright, metallic luster Conduct heat and electricity Malleable and ductile Properties of Nonmetals Nonmetals are electron LOVERS (Gain/ Take electrons in chemical reactions) Poor conductors of heat and electricity Usually brittle Lower melting points Many are gases at room temperature

Lesson 4: Chemical Formulas How do you write a chemical formula? Write the symbols and oxidation numbers for each ion. Write the ion with the positive charge on the left: Pb+4 O-2 Criss-Cross the charges by writing each charge as the subscript for the other. Ignore the signs. Pb+4 O-2 Pb2 O4 Simplify the ratio. Do not write the subscript 1: PbO2