The subshell letter:a) specifies the 3-D shape of the orbital. b) specifies the principal shell of the orbital. c) specifies the principal quantum number of the orbital. d) specifies the maximum number of electrons. e) none of the above

a) specifies the 3-D shape of the orbital

Explanation:

To determine the region where is more probable to find the electron, it is characterized by four quantum numbers:

- Principal quantum number (n) : represents the level, or shell, where the electron is. It varies from 1 to 7, and are represented by the letters K, L, M, N, O, P, and Q.

-Azimuthal quantum number (l) : represents the sublevel, or subshell. Is represented by the letters s, p, d, f, g, ... And by the numbers 0, 1, 2, 3, ... Each one has a 3-D shape, the s, for example, has a spherical shape.

-Magnetic quantum number (ml) : represents the orbital inside the subshell, and varies from - l to + l, passing by the 0. Each orbital can have at least 2 electrons.

-Spin quantum number (ms) : represents the spin of the electron, which can be + 1/2 or - 1/2.