I did do a few searches before writing this, and I found some mention of logical validity in a general node, but a simple summary of the definition, difference and relationship of both soundness and validity seems worthwhile.
An argument is logically valid iff the premises follow from the conclusion. This means that the premises necessarily entail the conclusion and the conclusion can therefore be deduced from the premises. For example,
Premise 1 - All toasters are items made of gold.
Premise 2 - All items made of gold are time-travel devices.
Conclusion - Therefore, all toasters are time-travel devices.
From the Internet Encyclopaedia of Philosophy
An argument is logically sound iff it is logically valid and also true. Therefore the example above is logically valid, but not logically sound. The premises are untrue, and the conclusion also happens to be untrue. The Internet Encyclopaedia of Philosophy amusingly gives the following example of an argument that is both logically valid and sound,
Premise 1 - All tigers are mammals.
Premise 2 - No mammals are creatures with scales.
Conclusion - Therefore, no tigers are creatures with scales.
There are actually a couple of things wrong with the way the second premise is formed that render it unsound, but let's keep it light. PANGOLINS. Pangolins are mammals and have scales. That will do, this is a valid but unsound argument, Premise 2 is untrue. It is irrelevant whether the conclusion is true in fact, the logical argument is unsound. Premise 2 is an unreliable determiner of the scaliness of tigers. We can see this even more clearly if we reformulate Premise 2 so that it is true in fact,
Premise 1 - All tigers are mammals.
Premise 2 - Some mammals are creatures with scales.
Conclusion - Therefore, no tigers are creatures with scales.
Let's do better, shall we? Here is an argument that is both logically valid and sound,
Premise 1 - When I do a lot of writing and don't get a lot of sleep, I start to feel a little high.
Premise 2 - I've been doing a lot of writing and haven't had a lot of sleep.
Conclusion - I'm starting to feel a little high.
I invite you to leave your own examples below.