For an argument to be valid, the form must be correct...AND THAT'S IT...premises and conclusions can be false as long as it follows argumentative form.
For an argument to be sound, all statements must be true. (premises and conclusions)
For it to be sound AND valid, premises and conclusions must be true, and must follow the argumentative form. Hope this helps, Good luck
All but your bottom two are correct; reasoning above.
To the responders who contest that number 2 is no, peruse the example:
Mitch is a cat
All cats are mammals
Therefore, Mitch is a mammal
This argument follows the argumentative form of:
A is B
All B are C
Therefore, A must be C-----This is Valid and sound
To make it sound but not valid (like number 2),
I will keep the truth value of the premises but switch the form:
Mitch is a cat
Some cats eat vegetables
Therefore, Mitch eats vegetables
As you can see, it doesn't necessarily follow that Mitch eats vegetables just because some cats do. This clearly shows the form is INVALID, meanwhile all premises and conclusions can be true at once. Your welcome