Electrochemistry1 Flashcards
Oxidation
Loss of Electrons
Reduction
Gain of Electrons
ELECTRONS MOVE FROM
REACTANT WITH ….. TO REACTANTS WITH ….
LESS
ATTRACTION FOR ELECTRONS…
…TO REACTANT WITH MORE
ATTRACTION FOR ELECTRONS
Electronegativity increases
upwards and to the right, with N, O, F being the most electronegative atoms in the periodic table
Oxidizing Agent
causes oxidation in another species (is reduced)
Reducing Agent
causes reduction in another species (is oxidized)
How would you define the O.N.?
The O.N. is the charge that the atom would have IF the electrons
were transferred completely to/from bonded atoms
O.N. number of an atom in its elemental form
An atom in its elemental form – oxidation number = 0 (e.g. Na or Cl2)
O.N. of a monoatomic ion
Monoatomic ion: Oxidation number = ion charge
O.N. of a molecule
The sum of oxidation numbers for all atoms in a molecule is equal to the charge on the molecule
O.N. assigned to a group 1 atom
Grp1 (+1)
O.N. assigned to a group 2 atom
Grp2 (+2
O.N. assigned to a H atom
H (+1)
O.N. assigned to a F atom
F (-1)
O.N. assigned to an O atom (most cases)
O (-2)
O.N. assigned to a group 17 atom
Grp17 (-1)
What are groups in the periodic table?
they are the columns of the periodic table
Oxidation
O.N. increases (becomes less electronegative)
Reduction
O.N. decreases (becomes more electronegative)
IN A BALANCED REDOX EQUATIONS:
# ELECTRONS LOST (OXIDATION) = # ELECTRONS GAINED (REDUCTION)
What is step 1 in balancing Redox Equations?
- Break “skeleton” equation (no spectator ions) into two half-reactions
What is step 2 in balancing Redox Equations?
- Balance atoms, everything but O&H, then O (add H2O), then H (add H+)
What is step 3 in balancing Redox Equations?
- Balance charge, add electrons (e–) to more positive side
What is step 4 in balancing Redox Equations?
- Scale (multiply) both halves so # electrons are equal, add coefficients
