What electron could have quantum numbers [tex]$n=4, l=2, m l$[/tex] [tex]$=-2, m_S=-\frac{1}{2}$[/tex] ?
A. A 4d electron
B. A [tex]$4 p$[/tex] electron
C. A [tex]$4 s$[/tex] electron
D. A [tex]$4 f$[/tex] electron
Answer (2)
The electron with quantum numbers n = 4 , l = 2 , m l = − 2 , and m s = − 2 1 is identified as a 4d electron. This is because the principal quantum number indicates the fourth energy level and the azimuthal quantum number indicates a d subshell. Thus, the correct option is A. A 4d electron.
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The principal quantum number n = 4 indicates the electron is in the fourth energy level.
The azimuthal quantum number l = 2 corresponds to a d subshell.
Combining these, the electron is identified as a 4d electron.
The correct answer is A. A 4d electron
Explanation
Understanding the Problem We are given the quantum numbers n = 4 , l = 2 , m l = − 2 , and m s = − 2 1 . We need to identify the electron based on these quantum numbers.
Energy Level The principal quantum number n represents the energy level of the electron. In this case, n = 4 , so the electron is in the fourth energy level.
Subshell Identification The azimuthal quantum number l describes the shape of the electron's orbital and corresponds to a specific subshell. The values of l are related to the subshells as follows:
l = 0 corresponds to an s subshell
l = 1 corresponds to a p subshell
l = 2 corresponds to a d subshell
l = 3 corresponds to an f subshell In our case, l = 2 , which means the electron is in a d subshell.
Electron Identification Combining the energy level ( n = 4 ) and the subshell ( l = 2 , which is a d subshell), we can identify the electron as a 4d electron. The quantum numbers m l and m s provide further details about the specific orbital and spin of the electron, but they don't change the overall identification of the electron as a 4d electron.
Final Answer Therefore, the electron with the given quantum numbers is a 4d electron.
Examples
Understanding electron configurations is crucial in chemistry for predicting how elements will interact to form chemical bonds. For example, knowing that carbon has the electron configuration 1 s 2 2 s 2 2 p 2 helps us understand why it can form four covalent bonds. Similarly, understanding the electron configuration of transition metals like iron is essential for understanding their catalytic properties. The quantum numbers help us describe the probability of finding an electron in a specific region around the nucleus, which is fundamental to understanding chemical behavior.
