## We started this lecture with a review of todays PLE. Everyone seems to have a good understanding of how to determine protons, electrons and neutrons using isotopic notation for atoms (PLE5.1 and 5.2). No problems with identifying metals and nonmetals in the periodic table.

## Most everyone is able to read a formula, however we did have a little problem with the number of oxygen molecules in C

_{6}H_{12}O_{6}. Many students thought 3 when actually there are no O_{2}molecules in the compound. Formula only tell us numbers of atoms of each element.## Finally the last problem in the PLE was a little challenging for some students so we worked it out in class.

## Problem #1:

## Only two istopes of copper are known to exist,

^{63}Cu has a isotopic mass of 62.9295989 u and^{65}Cu has a isotopic mass of 64.9277929 u. The percent abundance for^{63}Cu is 69.17% and for^{65}Cu the percent abundance is 30.83%. Calculate the atomic weigh, in atomic mass units (u) for the element copper.## Next we talked about the periodic table defining rows, periods and groups. We named the alkali metals, alkaline earth metals, transition metals, boron, carbon, nitrogen, chalogen, halogen and inert gases.

## We identified metals, nonmetals and metalloids.

## Then we started talking about compounds, specifically ionic and covalent compounds. I talked about the properties of two substances, NaCl and glucose (C

_{6}H_{12}O_{6}).## Everyone should not be able to do problems PS2.1 - PS2.7. We'll finish the last three problems in class on Wednesday.