Which of the following is correct for $He$?

For a $d$-electron,the orbital angular momentum is:

Which of the following statements are correct?
$(A)$ The electronic configuration of $Cr$ is $[Ar] 3d^5 4s^1$.
$(B)$ The magnetic quantum number may have a negative value.
$(C)$ In the ground state of an atom, the orbitals are filled in order of their increasing energies.
$(D)$ The total number of nodes is given by $n-1$.
Choose the most appropriate answer from the options given below.

The electronic configuration of fluorine is

Figure $1$ shows the electron density distribution for a $2s$ orbital. Figure $2$ shows the radial wave function plot for a $2s$ orbital. Which of the following points $(A, B, C, D)$ in Figure $2$ most accurately represents the spherical nodal surface as shown in Figure $1$?

The maximum number of electrons in a subshell of an atom is determined by which of the following expressions?