What are the quantum numbers for Bromine?

1 Answer

Answer:

Quantum Numbers define the character of an electron in an energy specific orbital. They do not define an element.

Explanation:

4 Quantum Numbers define the character of an electron in an energy specific orbital.

According to the Pauli Exclusion principle, no two electrons can have the same set of 4 quantum numbers. This is significant in that elements with multiple electrons cannot have more than two in a single orbital.

Think of the set of Quantum Numbers for an electron as being a 'discrete energy window' for that electron and no other electron in the element's electron configuration can occupy the same energy window.

The 4 Quantum Numbers (QN) and what they describe are:

  • Principle QN (#n#) => Defines Principal Energy Level
  • Orbital QN (#l#); also known as Angular Momentum QN => Shape of Orbital
  • Magnetic QN (#m_l#) => Orientation of orbital in 3 dimensions
  • Spin QN (#m_s#) => the spin of the electron, up or down #pm 1/2#, respectively).

The 4 Quantum Numbers for the 'last' electron to fill a Bromine electronic configuration would be the electron in the half-filled #4p# orbital...

#=> (n, l, m_l, m_s) = (4, 1, {-1,0,+1}, -1/2) =># represents only one of 35 electrons in the neutral Bromine atom.

We choose the set of #m_l# because the three #4p# orbitals are identical and thus there are three configurations that have the same energy:

#4p_x^2 4p_y^2 4p_z^(color(blue)(1))#

#4p_x^2 4p_y^(color(blue)(1)) 4p_z^2#

#4p_x^(color(blue)(1)) 4p_y^2 4p_z^2#