OXIDISING AGENTS AND REDUCING AGENTS Flashcards
What is the oxidation number?
The charge that an ion has or the charge that it would have if the species were fully ionic.
The oxidation number of an uncombined element is …
zero.
The sum of the oxidation numbers of all the elements in a neutral compound is …
zero.
The sum of the oxidation numbers of all the elements in an ion is …
equal to the charge of the ions.
The more electronegative element in a substance is given …
a negative oxidation number.
The oxidation of fluorine is always …
-1
The oxidation number of hydrogen is …
+1, except when combined with a less electronegative element. It then becomes -1.
The oxidation number of oxygen is …
-2, except in peroxides where it is -1 and when combined with fluorine when it is positive.
An element is oxidised when…
It’s oxidation number increases.
An element is reduced when…
It’s oxidation number decreases.
What is disproportionation?
The simultaneous oxidation and reduction of an element in a single reaction.
What is the systematic name?
The roman numeral written in brackets. When an element can have more than one oxidation state. e.g. iron(II) chloride.
Deduce the formula for iron(II) sulfate.
- The formula of the iron(II) ion is Fe²⁺
- The formula of the sulfate ion is SO₄²⁻
Deduce the oxidation number of chlorine in NaCl.
- The oxidation number of Na is +1.
- The two oxidation numbers must add up to zero, so the Cl must be -1.
How can you determine whether a reaction is an example of a redox reaction?
-Look at the oxidation numbers and see if both oxidation and reduction are occurring.
