Which of the following statements are correct?

1. Electron density in $\mathrm{xy}$ plane in $3{\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$ orbital is zero.

2. Electron density in $\mathrm{xy}$ plane in $3{\mathrm{d}}_{{\mathrm{z}}^2}$ orbital is zero.

3. $2\mathrm{s}$ orbital has only one spherical node in it.

4. For $2{\mathrm{p}}_{\mathrm{x}}$ orbital $\mathrm{yz}$ is the nodal plane.