The number of radial nodes of $3s$ and $2p$ orbitals are respectively.

Give the symbol of the element with the lowest atomic number that has three $2p$ electrons.

Statement $1$: The energy of an electron is determined by the principal quantum number.
Statement $2$: The principal quantum number $(n)$ indicates the distance of the electron from the nucleus.

The electronic configurations of four elements are given in brackets: $L\,(1s^2, 2s^2 2p^1)$; $M\,(1s^2, 2s^2 2p^5)$; $Q\,(1s^2, 2s^2 2p^6, 3s^1)$; $R\,(1s^2, 2s^2 2p^2)$. Which element would most readily form a diatomic molecule?

The correct order of increasing energy of atomic orbitals is

Which of the following sets of quantum numbers is possible?