At Westonci.ca, we provide clear, reliable answers to all your questions. Join our vibrant community and get the solutions you need. Explore in-depth answers to your questions from a knowledgeable community of experts across different fields. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

Which electron configuration represents the electrons of an atom in an excited state?
(1) 2–8–1 (3) 2–8–17–6(2) 2–8–6 (4) 2–8–18–5


Sagot :

Answer is: (3) 2–8–17–6.

1) This is ground state of sodum atom.

Electron configuration of sodium atom: ₁₁Na 1s² 2s² 2p⁶ 3s¹.  

Atomic number of sodium is 11, it means that it has 11 protons and 11 electrons, so atom of sodium is neutral.  

2) This is ground state of sulfur atom.

Sulfur electron configuration: ₁₆S 1s²2s²2p⁶3s²3p⁴.


Sulfur has six valence electrons (3s²3p⁴), in 3s orbital, two electrons are paired, in 3p orbital, two electrons are paired and two are unpaired.

4) This is ground state of arsenic atom.

Electron configuration of arsenic atom:

₃₃As 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³.

Electron configuration represents an excited state : (3) 2–8–17–6

Further explanation

In an atom there are levels of energy in the shell and sub shell

This energy level is expressed in the form of electron configurations.

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d and f. The maximum number of electrons for each sub shell is

  • s: 2 electrons
  • p: 6 electrons
  • d: 10 electrons and
  • f: 14 electrons

Charging electrons in the sub shell uses the following sequence:

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.

Determination of electron configurations based on principles:

  • 1. Aufbau: Electrons occupy orbitals of the lowest energy level
  • 2 Hund: electrons fill orbitals with the same energy level
  • 3. Pauli: no electrons have the same 4 quantum numbers

According to Niels Bohr, electrons surround the nucleus of an atom on a path called the electron shell. Each shell has an energy level. The further from the core, the higher the energy level

Maximum electrons of shells :

  • K shell: 2 electrons
  • L shell: 8 electrons
  • M shell: 18 electrons
  • N shell: 32 electrons
  • O shell: 50 electrons
  • P shell: 72 electrons

The maximum number of electrons in each shell can be formulated = 2n² (n = shell number)

Electrons can move the shell up or down by releasing energy or absorbing energy

Excited electrons show higher electron transfer to the shell by absorbing energy

So it can be concluded that there are 2 conditions :

Ground state is the state of electrons filling skins with the lowest energy levels.

Excited state is the state of electrons which occupy a higher energy level

The state of excited electrons can be seen from the presence of electrons which do not fill the skin completely but fill the skin afterwards

From the electron configuration , option 3 shows the excitation of one electron in the M shell towards the N shell, which should have a configuration in the ground state:

2–8–18–5

Learn more  

element X  

brainly.com/question/2572495  

electrons and atomic orbitals  

brainly.com/question/1832385  

about subatomic particles statement  

brainly.com/question/3176193  

Keywords: electron configurations, the shell of atoms, excited state

We appreciate your time. Please revisit us for more reliable answers to any questions you may have. We hope you found this helpful. Feel free to come back anytime for more accurate answers and updated information. Keep exploring Westonci.ca for more insightful answers to your questions. We're here to help.