Counting Atoms, Naming, and Bonding
So…this is chemistry.
Classification of Elements
• Uses position on the periodic chart (dictated by how the element acts) to tell what the element “is”–We already did this with the coloring of
the chart
Valence electrons
• The number of electrons in the outermost shell
• Tells a bit about how it will react• Can tell by position on the periodic chart
Counting Atoms
• So two elements combined makes a compound. There is bonding involved.
• You need to COUNT the number of each type of atom in a compound
• You can tell this from the formula
Some more examples
Magnesium fluoride (MgF₂)• One atom of
Magnesium• Two atoms of
Fluorine
Sodium chloride (NaCl)• One atom of
Sodium• One atom of
Chlorine
You can name compounds based on what they are made of
• Mono - 1• Di - 2• Tri - 3• Tetra - 4• Penta - 5
• Hexa - 6• Hepta - 7• Octa - 8• Nona - 9• Deca - 10
Some examples…
• Nitrogen oxide• Dinitrogen oxide• Nitrogen dioxide• Dinitrogen
pentoxide• Dinitrogen trioxide
So let’s try counting a few…
•H₂O•LiF•K₂S
•H2SO4
•CH4
•C8H10N4O2
Another complication…
•2 K₂S•3 H₂O•4 H₂SO₄
Yet another wrench…
•3 Ca(NO3)2
•2 Fe(NO3)2
•5 BaSO4