The quantum numbers of four electrons are given below.The correct order of decreasing energy of these electrons is,
Correct answer: C. Electron 3 > Electron 2 > Electron 4 > Electron 1
- A. Electron 3 > Electron 1 > Electron 4 > Electron 2
- B. Electron 4 > Electron 2 > Electron 3 > Electron 1
- C. Electron 3 > Electron 2 > Electron 4 > Electron 1
- D. Electron 2 > Electron 4 > Electron 3 > Electron 1
Explanation
To determine the order of decreasing energy of electrons, use the (n+l) rule where 'n' is the principal quantum number and 'l' is the azimuthal quantum number. The electron with the highest (n+l) value has the highest energy. If two electrons have the same (n+l) value, the one with the higher 'n' value is more energetic. Electron 3 has an (n+l) value of 5, making it the most energetic. Electrons 2 and 4 both have an (n+l) value of 4, but Electron 2 has a higher 'n' value, giving it more energy. Electron 1, with an (n+l) value of 3, has the lowest energy. Thus, the correct order is Electron 3 > Electron 2 > Electron 4 > Electron 1. The other options do not correctly apply the (n+l) rule.
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About Quantum Numbers
Quantum numbers describe an electron's energy level, subshell, orbital orientation and spin. You examine the principal, azimuthal, magnetic and spin quantum numbers, their allowed values, orbital capacity and how they determine electronic configurations and distinguish electrons within an atom.
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