2 shells because if you do the electronic configuration:
2,7 which adds up to 9
7 stands for the group it in and it also stands for how many electrons are in the outer shell.
the amount of spaces stands for which period its in therefore it in period 2
The equation is:
3 O₂ + 4 Co → 2 Co₂O₃
Oxidation half reaction:
Co → Co³⁺ + 3 e
Reduction half reaction:
O₂ + 4 e → 2 O²⁻
To balance the equation number of electrons lost must be equal to number or electrons gained so we must multiply oxidation half time 4 and reduction half times 3
At its discovery, benzene was recognized to be a unique unsaturated hydrocarbon because it either failed to react, by substitution with common reagents or reacted by addition that led to reactions with alkenes.
<h3>What are unsaturated hydrocarbons?</h3>
Unsaturated hydrocarbons are the hydrocarbons which have at least on double or triple carbon to carbon bond in its molecules.
All other hydrocarbons are unsaturated except for the alkanes and the cyclic alkanes.
Benzene is an aromatic compound which has a special six-carbon ring with are resonance structure reflecting the presence of three carbon-carbon bonds in its molecules.
The common reactions of unsaturated hydrocarbons are substitution and addition reactions.
However, benzene on its discovery did not undergo any of these reactions.
In conclusion, benzene showed a difference when compared with the common unsaturated hydrocarbons as it did not undergo either substitution or addition reactions.
Learn more about benzene at: brainly.com/question/6028840
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