If $\nvDash\phi$ must it be $\vDash\lnot\phi$? If $\nvDash\phi$ where $\phi$ first order sentence must it be $\vDash\lnot\phi$?

Question

I got stuck at this problem:

Determine whether the following sentences are true or false in first order logic:

(1) If $\nvDash\phi$ must it be the case that $\vDash\lnot\phi$?

(2) If $\nvDash\phi$ where $\phi$ is a first order sentence must it be the case that $\vDash\lnot\phi$?

I am stucked when I try solve this problem and I am not sure I am fully understand those symbols when it comes to first order logic.

Thanks for any hint or help.