How would you find the quantum numbers for an atom?

1 Answer
Dec 1, 2015

Answer:

See explanation.

Explanation:

Quantum numbers are considered as the coordinates that will give an idea about the location of an electron in an atom.

There are four different quantum numbers:

  1. Principal Quantum Number (n) has integral values 1, 2, 3, ... This number determines the size and energy of the orbital.
  2. Angular Momentum Quantum Number (#l#) associated with the number of different types of subshells in an energy level. #l=0, 1, 2, 3, ... (n - 1)#.
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  3. Magnetic Quantum Number (#m_l#) describes the orientation (direction) in space of each orbital and can have integral values from #- l# through #+l#.
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  4. Electron Spin Quantum Number (#m_s#) describes the direction of spin of the electron(s) in an orbital. There are only two values of #m_s, +1/2 "and" -1/2#.

Note that no two electrons may have identical sets of all 4 quantum numbers.

Consider the electron configuration of sodium #""_11Na#:

#""_11Na:1s^(2)2s^(2)2p^(6)color(red)(3)color(blue)(s)^(color(green)(1))#

What would be the set of quantum numbers of the valence electron of sodium:
#color(red)(n=3)#: third energy level.
#color(blue)(l=0)#: sublevel or subshell #s#.
#color(blue)(m_l=0)#: one possible orbital.
#color(green)(m_s=+1/2) or color(green)(-1/2)#: the electron spin.