Topic 3 - Redox I Flashcards
What is oxidation?
When an element loses electrons or has an increase in oxidation number (OILRIG)
What is reduction?
When an element gains an electron or has a decrease in oxidation number (OILRIG)
What is an Oxidation number?
Oxidation numbers are numbers that are assigned to atoms or ions to show the extent to which they have been oxidised
What is the oxidation number of uncombined elements?
0
e.g Cl2, Fe etc.
What is the oxidation number of a neutral compound?
The sum of the oxidation numbers of all the elements in the compound = 0
e.g MgF2, Mg = +2 and F = -1
What is the oxidation number of ions?
The charge of the ion
e.g Cl- = -1, Fe2+ = +2, Fe3+ = +3
What is the oxidation number of complex ions (Ions containing more than one atom)?
The sum of all the oxidation numbers in the compound = charge of the ion
e.g NH4+, SO42-
What is the oxidation number of hydrogen in a compound?
+1
What is the oxidation number of hydrogen when bonded to a metal as a hydride?
-1
What is the oxidation number of oxygen in a compound?
-2
What is the oxidation number of oxygen when in hydrogen peroxide?
-1
What is the oxidation number of fluorine when in a compound?
-1
What is the oxidation number of metals in a compound?
It is positive and usually the same as the group number
What is the oxidation number of transition metals in a compound?
Transition metals are positive and have varying oxidation numbers
What is the oxidation number of non-metals in a compound?
It is negative with values up to that of the group number