Quantum Numbers Activity

Warm-Up Write the electron configuration for Uranium Now, write the abbreviated electron configuration for Europium

Electron Configurations The distribution of electrons into the various energy shells and subshells in an atom in its ground state is called its electron configuration. Each energy shell and subshell has a maximum number of electrons it can hold. s = 2, p = 6, d = 10, f = 14. Based on the number of orbitals in the subshell. We place electrons in the energy shells and subshells in order of energy, from low energy up. Aufbau principle. Tro's "Introductory Chemistry", Chapter 9

Quantum Numbers Like giving each electron its own address Quantum numbers tell us properties of the atomic orbitals, and electrons, in an atom Like giving each electron its own address We understand this idea from electron configurations An orbital is a 3-D region of an atom where there is a high probability of finding electrons (NOT an actual ring & NOT like the planetary orbitals)

Principal Quantum Number Angular Momentum Quantum Number Magnetic Quantum Number Spin Quantum Number

Textbook You will need a textbook to look up information about the quantum numbers.

Know for each Quantum # Definition Symbol The allowed values An example A visual representation of the quantum number

Review Quantum Numbers as a Class Discussion of the 4 types of quantum numbers and there properties

Quantum Number Review Notes

Quantum Numbers Used to describe various properties of the orbitals in an electron configuration Each electron is assigned a set of four quantum numbers which, in order, are n, l, ml , and ms Like giving each electron its own address

Principle quantum number Definition: indicates the main energy level occupied by the electron Symbol: n Values: (written as integers) 1,2,3,4,5,6,7

Angular Momentum Quantum Numbers Definition: indicates the shape of the orbital Symbol: l Values: 0 = s 1 = p 2 = d 3 = f For a specific energy level, the number of orbital shapes available is equal to n -1

Magnetic Quantum Numbers Definition: represents the orientation of an orbital around the nucleus Symbol: ml Values: for a p-orbital -1, 0 , 1

Spin Quantum Numbers Definition: represents the spin states of electrons in an orbital Symbol: ms Values: +1/2, - ½

Can an e- be described by the following set of quantum numbers? n=2, l=1, ml= -1 All quantum numbers are allowed values

Can an e- be described by the following set of quantum numbers? n=1, l=1, ml= +1 Not possible. The value of l must be less than the value of n.

Can an e- be described by the following set of quantum numbers? n=7, l=3, ml= +3 All the quantum numbers are allowed values.

Can an e- be described by the following set of quantum numbers? n=3, l=1, ml=-3 Not possible. The value of ml must be in the range -l to +l

Replace the ? Mark with an appropriate quantum number. n=3, l=1, ml=? n=4, l=?, ml=-2 n=?, l=3, ml=?

Can an e- be described by the following set of quantum numbers? n=2, l=1, ml=-2 n=3, l=2, ml=+2 n=4, l=3, ml=+3 n=5, l=2, ml=+3

Writing Quantum Numbers You can identify the quantum numbers for any electron in an element Start by writing out the the electron configuration and orbital diagram for the element Locate the electron in the orbital diagram that you are solving the quantum number for Determine the 4 quantum numbers

Hydrogen’s electron Write electron configuration Draw orbital diagram ml= 0 ms= +1/2

Helium’s second electron Write electron configuration Draw orbital diagram n= 1 l= 0 ml= 0 ms= -1/2

Lithium’s third electron Write electron configuration Draw orbital diagram n= 2 l= 0 ml= 0 ms= +1/2

Flourine’s 6th electron Write electron configuration Draw orbital diagram n= 2 l= 1 ml= 0 ms= +1/2