What is the number of radial nodes in the $2s$ orbital?

The azimuthal quantum number for the last electron of the $Na$ atom is:

Which of the following statement$(s)$ is/are true?
$A$. If two orbitals have the same value of $(n+l)$, the orbital with lower value of $n$ will have lower energy.
$B$. Energies of the orbitals in the same subshell increase with increase in atomic number.
$C$. The size of $2p_x$ orbital is less than the size of $3p_x$ orbital.
$D$. Among $5f, 6s, 4d, 5p$ and $5d$ orbitals, none of the orbitals have $2$ radial nodes.

The ground state term symbol for an electronic state is governed by

The maximum number of electrons in an atom with $l = 2$ and $n = 3$ is

Which of the following is not a permissible arrangement of electrons in an atom?