 What do we use roman numerals for in everyday life?  Name what the letters in roman numerals stand for (I, V, X, etc.)  What can chemical formulas tell us?

Mr. Schlamb

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 Chemical formulas tell us the number of each atom in a compound  Dihydrogen oxide is H 2 O or water  Carbon Dioxide tells us what?

 Ionic compounds consist of only positive and negative atoms.  For example HCl is composed of positive hydrogen atoms and negative chlorine (chloride) atoms

 Monoatomic ions– ions formed from a single atom  Rules:  Nitrogen and most group 15 elements form -3 ions  Oxygen and most group 16 elements form -2 ions  Fluorine and most group 17 elements form -1 ions  Lithium and most group 1 elements form +1 ions  Beryllium and most group 2 elements form +2 ions

 Cations keep their name so a sodium ion Na +1 will still be called sodium  Anions change their name, the ending is dropped and replaced with “ide”, Cl - is called chloride  Practice what will Be +2, O -2, and F - be called?

 I will put Table 1 on Moodle or have a copy for you next class to use  If you would like you can put this in your notebook if you want  Some of these will be important to remember