Review of Basic Chemistry

A: Subatomic Particles Atoms are composed of protons, electrons, and neutrons. Electrons carry a negative charge and move around the nucleus. The nucleus is made up of positively charged protons, and neutrons, which have no electrical charge.

A: Subatomic Particles Name Charge Symbol Mass Location 1 amu 1/1837 amu 1 amu = 1.67 x 10-24 g

B: Structure of Atoms In a neutral atom, the number of proton (atomic number) = the number of electrons. The mass number = # protons + # neutrons.

Bohr-Rutherford Diagram One way to show the structure of an atom (up to atomic #20) Each electron orbital/shell can hold a certain number of electrons: 1st orbital can hold up to 2 e- (inner most) 2nd orbital can hold up to 8 e- 3rd orbital can hold up to 8 e- 4th orbital can hold up to 2 e-

Bohr-Rutherford Diagram of a Fluorine Atom:

Practice Time

C: The Periodic Table The periodic table is made of three types of elements: Metals (give up electrons) Non-metals (take electrons) Metalloids (bit of both)  boron, silicon, germanium, arsenic, antimony, tellurium, polonium

C: The Periodic Table A chemical group/family is a vertical column of elements that have similar physical and chemical properties. On the periodic table there are 18 vertical groups. Column 1: alkali metals Column 2: alkaline earth metals Column 3-11: transition metals Column 17: halogens Column 18: noble gases/inert gas Two Rows at Bottom: rare earth metals

Based only on atomic properties the Periodic Table would look like this! For convenience, we pull out the rare earths so the Periodic Table looks like what we see

Periods Periods are horizontal rows of elements. The first period (row) contains 2 elements. The second period (row) contains 8 elements etc. The properties of an element gradually change across a period. The size of an atom gets smaller as you move across a period.

Valence Electrons Sodium atom Electrons that occupy the outermost orbital are responsible for the chemical behavior of the element. Sodium atom

D: Lewis Diagrams Lewis diagrams show the number of electrons in the outermost orbit only.