Answer :
Answer:
Choice C.) A [tex]4\, \rm d[/tex] electron.
Explanation:
In an atom, each electron has a unique set of four quantum numbers.
[tex]n[/tex] is the principal quantum number. It gives the index of the energy shell that contains this electron. Hence, it must be a positive whole number (1, 2, 3, etc.) In this case, [tex]n = 4[/tex]. Hence, this electron is in the fourth main energy shell. Think about this number as giving the size of the orbital that holds this electron.
[tex]l[/tex] is the orbital angular momentum quantum number. It gives the type (shape) of the orbital that holds this electron. [tex]l[/tex] should also be a whole number. However, unlike [tex]n[/tex], the value of [tex]l[/tex] starts from [tex]0[/tex] and has an upper bound, [tex](n - 1)[/tex]. Here are the meanings for some common values of [tex]l[/tex]:
- [tex]l = 0[/tex] corresponds to an s-orbital. (Requires [tex]n \ge 1[/tex].)
- [tex]l = 1[/tex] corresponds to a p-orbital. (Requires [tex]n \ge 2[/tex].)
- [tex]l = 2[/tex] corresponds to a d-orbital. (Requires [tex]n \ge 3[/tex].)
As a side note, in each energy level, each type of orbital can hold more than one electrons. The other two quantum numbers, [tex]m_l[/tex] and [tex]m_s[/tex], help distinguish between these electrons. However, that's not very relevant to this problem.
