Number

This Chemistry lesson is titled Whats the Difference between Mass Number and Atomic Weight and will give a detailed explanation of the topic.

Craig Beals answers the question, "How many places after the decimal should my answer have?". He shows the importance of significant figures, how to count significant figures, and how to accurately show a mathematical answer in the correct number of significant figures.

Many practice problems for how to calculate and determine oxidation numbers, often referred to as oxidation states. To figure out oxidation numbers for elements in a compound, we have to look on the periodic table and consult a list of rules. For neutral compounds, the oxidation numbers add up to zero. For polyatomic ions, the oxidation numbers add up to charge of the ion.