The maximum number of electrons that can be accommodated in a subshell is determined solely by the azimuthal quantum number ($l$) using the formula $2(2l + 1)$.

1. Identify the Subshell: $l = 0 \rightarrow s$ $l = 1 \rightarrow p$ $l = 2 \rightarrow d$ $l = 3 \rightarrow f$ Given $l = 3$, the subshell is an f-subshell (specifically 4f, since $n=4$).

2. Calculate Electron Capacity: Number of orbitals = $2l + 1 = 2(3) + 1 = 7$ orbitals. Each orbital holds a maximum of 2 electrons (Pauli Exclusion Principle).

• Total electrons = $2 \times 7 = 14$.

This is consistent with the electronic configuration of f-block elements (Lanthanoids and Actinoids), where the f-orbitals are progressively filled with up to 14 electrons .