What does redox mean?
Referring to reactions which involve both reduction and oxidation
What is oxidation?
What is reduction?
- O - losing electrons (oxidation no. increases)
- R - gaining electrons (oxidation no. decreases)
remember OIL RIG
TRUE or FALSE: are all reactions redox?
FALSE - most reactions are REDOX or NEUTRALISATION but NEVER BOTH
What is meant by oxidation state/number?
Tells us how many e- are used when an element is bonded to other atoms in a compound
determines what happens to elements during oxidation and redox reactions
What is the Oxidation no. for uncombined elements?
0 - e.g. Cl2, Mg etc.
What is the oxidation no. for metals?
Oxidation no. is corresponds their group no. - group 1 is +1
What is the oxidation no. for fluorine?
What is the oxidation no. for hydrogen?
- Fluorine is ALWAYS -1
- Hydrogen when compound in a compound is mostly +1
* But is -1 in metal hydrides e.g. NaH
What is the oxidation no. for oxygen?
What is the oxidation no. for chlorine?
- Oxygen is mostly -2 EXCEPT in peroxides it is -1
- Chlorine is generally -1 BUT can change
What is the oxidation no. for neutral molecules?
What is the oxidation no. in compound ions?
- Sum is ALWAYS 0 for neutral molecules
- Sum is equal to the charge on the ion
What are Roman numerals used to indicate?
When an element can exist in more than one oxidation no.
Typically in transition metals or oxyanions
What is an oxyanion?
Negative ions that contain oxygen e.g. SO42-
What an oxidising agent?
- Atom that gains electrons - it is reduced
- oxidises another another species
What is a reducing agent?
- Atom that loses electrons - it is oxidised
- Reduces another species
