Will a contradiction always have only false values?
A tautology will always have true vales, is the opposite true for contradictions?
For example: $(p \ \& \ q) \ \& \ (p \ \& \ \neg q)$ has the truth table:
Contradictions will always end in all entries of the rightmost column of a truth table being only "F".
$a \land b\land c \land .... \land p\land \lnot p$ will never be true, because $p \land \lnot p$ is False, and no matter what you "and" to that to form a new statement, it will still be false. Any statement for which no matter the assignment of truth-values to the propositions, ends in the evaluation of False, is a contradiction.
Please see The Principle of Non-Contradiction, a Wikipedia entry.
A contradiction is something that is always false, regardless of it's truth values.