How many total orbitals are present in the $4f$ subshell?

To which block does an element with the electronic configuration $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^1$ belong in the periodic table?

Which orbital notation does not have a spherical node?

The total number of orbitals in an energy level designated by principal quantum number $n$ is equal to

Assertion :- In $H$-atom,the energy of $3d$-level is smaller than $4s$-level.
Reason :- In multi-electron species,an orbital with lower value of $(n+\ell)$ has energy smaller than the orbital with larger value of $(n+\ell)$.

The orbital angular momentum of a $3p$ electron is