The principal quantum number of an orbital defines:
The options:
a) The size of the atom
b) The energy level of the orbital
c) The shape of the orbital
d) The spatial orientation of the orbital
e) The spin of the electrons in each orbital
b) The energy level of the orbital
b) The energy level of the orbital
The principal quantum number (denoted by the symbol "n") of an orbital defines the energy level of the orbital. Therefore, the correct answer is option b) The energy level of the orbital.
To understand why the principal quantum number defines the energy level, we need to dive into the concept of atomic structure.
In quantum mechanics, electrons in an atom are organized into energy levels, or shells, around the nucleus. Each energy level is associated with a specific range of energy values. These energy levels are further divided into sublevels, which are characterized by subsidiary quantum numbers.
The principal quantum number (n) determines the size and energy of the orbital. The larger the value of n, the higher the energy level and the farther the electron is from the nucleus. Each energy level can accommodate a specific number of electrons: 2n². For example, the first energy level (n=1) can hold a maximum of 2 electrons, the second energy level (n=2) can hold a maximum of 8 electrons, and so on.
This means that the value of the principal quantum number specifies which energy level an electron occupies. It directly influences the energy of the electron in that particular orbital. So, option b) The energy level of the orbital is the correct answer.