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Criss-cross notes. Jump Jump. Criss-Cross Method. Criss-cross is a _________ to help you find chemical __________ when you _________ atoms. shortcut. formulas. combine. **Formulas contain both the ________ in a compound and the _______ of that element. elements. amount. How Many?.
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Criss-cross notes Jump Jump
Criss-Cross Method Criss-cross is a _________ to help you find chemical __________ when you _________ atoms. shortcut formulas combine **Formulas contain both the ________ in a compound and the _______ of that element. elements amount
How Many? 1 sodium NaCl = 1 chlorine 1 magnesium MgCl2 = 2 chlorines This number is called a ________ subscript It tells you the _______ of the atom ________ in front of it! amount directly
To get started… First – you need to determine the _________ number for each atom. oxidation You can find them in the ______- ______ corner on the Periodic Table. upper right
Cl Oxidation Oxidation numbers are the _____ that will form when atoms _________ their _________ shells. ions complete valence Oxidation number Cl-1
More than one? Many atoms have more than one oxidation state! We will use the ______ one listed! first (This is the one most _________ formed in nature!) commonly
Criss-Cross will make you... Find the correct formula for a compound!! • Use the oxidation #’s • Put the _______ one first positive H+1 + O-2 H2O
What just happened? By switching the numbers, the _________ number of one atom becomes the _________ for the other! oxidation subscript This also makes sure that we end up with a _______ compound – all the ________ of the ions add up to ______. neutral charges zero
Stuff to remember… ‘Ones’ are ________. (Think Math!) invisible If both of your ions have the _____ oxidation number -- ______ to the ______ common number! same reduce lowest It will make more sense after examples…
Criss-Cross practice +2 -1 CaBr2 Ca + Br +2 -1 Mg+ Cl MgCl2 +2 -2 Sr2O2 SrO Sr + O
What's my name? Don’t forget the rules for naming: 1. ______ always goes first! Metal 2. ________ goes second – and ends in _____! Nonmetal “-ide” Have fun!!!