Calculating Oxidation Numbers - Redox (5.2) Flashcards
Define oxidation number
The oxidation number (oxidation state) of an element is the formal charge the atom would have if the compound were ionic
What are the 3 general guidelines for assigning oxidation numbers?
- Elements will usually aim to achieve a full shell of electrons
- The more electronegative element will be negatively charged
- The less electronegative element will be positively charged
Name the 3 rules for oxidation states
- Elements have an oxidation state of 0
- Some elements nearly always have the same oxidation number in a compound (F, G1&2 metals, H, O)
- The sum of all oxidation numbers must equal the overall charge so you can usually calculate the oxidation numbers of everything else
In what order should elements that nearly always have the same oxidation number be assigned?
F -1 G1 metals +1 G2 metals +2 H +1 O -2
(Assign from top to bottom)
How does the oxidation state change when oxidation occurs?
When oxidation occurs, the oxidation state becomes more positive
How does the oxidation state change when reduction occurs?
When reduction occurs, the oxidation state becomes more negative
What is a monatomic ion?
Where the oxidation number of an element in a monatomic ion is the same as the charge on that ion
What is a polyatomic ion?
Where the total charge on any polyatomic equals the SUM of the oxidation numbers
Some elements can take more than one oxidation state. True or false?
True
How can oxidation states be represented in the names of compounds?
Using Roman numerals
How does transition metal catalysis work (brief answer)?
The reactions can be catalysed in a two-step reaction, where oxidation state of the atom can change
