Oxidation Numbers Flashcards
If oxidation occurs what can also be said to happen?
Then another substance must be being reduced - it is impossible for a substance to be oxidised without another being reduced.
What does the oxidation number represent?
The combining power of an element.
What is oxidation?
The addition of oxygen to an element or compound
Removal of hydrogen from a compound
Loss of electrons
Increase in oxidation number.
What is reduction?
Removal of oxygen from a compound
Addition of Hydrogen to an element or compound
Gain of electrons
Decrease in oxidation number.
What is the oxidation number of an element in an uncombined state?
Zero
What is the oxidation number equal to in an ionic compound?
The charge on the ion. E.g Na anion has a oxidation number of +1
What is the sum of oxidation numbers in a uncharged compound equal to?
Zero
What is the sum of the oxidation numbers in an ion equal to?
The charge on the ion.
What is the oxidation number of all group one elements?
+1
What is the oxidation number of all group two elements?
+2
What is the oxidation number of Aluminum?
+3
What is the oxidation number of hydrogen?
+1
Except on metal hydrides.
What is the oxidation number of Flourine?
-1
What is the oxidation number of chlorine?
-1
Except in compounds containing oxygen and flourine.
What is the oxidation number of oxygen?
-2
Except in peroxides, superoxides, and compounds containing flourine.
