Ch.8 - Periodic Properties of the ElementsSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

The fourth quantum number, ms, determines the spin of an electron within an atomic orbital. 

The Fourth Quantum Number

Whereas the first 3 quantum numbers describe the atomic orbital where you find the electron, the final quantum number, ms, describes spin the electron possesses. 

Concept #1: Spin Quantum Number Part 1

The Pauli Exclusion Principle implies that two electrons in the same atomic orbital cannot spin in the same direction so as to avoid having the same four quantum numbers. 

Concept #2: Spin Quantum Number Part 2

Example #1: State the electron configuration of boron and list the four quantum numbers of the 1st and the 5th electron. 

Additional Problems
Which of the following is a possible set of quantum numbers for a 3d electron?a)  n=4, l=3, m l=2, ms=-1/2 b)  n=3, l=2, m l=0, ms=-1/2c)  n=3, l=1, m l=1, ms=+1/2d)  n=3, l=3, m l=2, ms=+1/2e)  n=3, l=0, m l=0, ms=+1/2
How many electrons can have the following quantum numbersa) n=3, l=1, ms=1/2 b) n=4, m l = -1
What is the smallest acceptable value for the missing quantum number?n = ?, ℓ = 2, mℓ = 0, ms = +1/2A) 4B) 3C) 1D) 5E) 2
Which of the following set is an acceptable set of quantum numbers?      a.  n = 0, l = 0, m l = 0, m s = +1/2b.  n = 2, l = 1, m l = 2, m s = −1/2c.  n = 2, l = 0, m l = 0, m s = 1d.  n = 1, l = 1, m l = 0, m s = −1/2e.  n = 3, l = 1, m l = −1, m s = −1/2
Which set of quantum numbers is not possible?a) n = 2, l = 1, m l, = +1, m s = –1/2b) n = 3, l = 2, m l = +1, m s = +1/2c) n = 4, l = 4, m l = –1, m s = +1/2d) n = 5, l = 2, m l = 2, m s = –1/2
For an electron that has quantum numbers n = 3 and m l = 2, which of the following is true?A) it must have the quantum number m s = + 1/2B) it must have the quantum number l = 1C) it may have the quantum numbers, l = 0, 1, 2D) it must have the quantum number l = 2E) none of these answers apply to this electron
Which of the following represents an impossible set of quantum numbers for an electron in an atom?a. 2, 1, -1, -1/2 b. 1, 0, 0, +1/2c. 3, 3, 3, +1/2 d. 5, 4, -3, +1/2 e. 5, 4, -3, -1/2
Which one of the following represents a 2p electron in an atom?a. 2, 1, -1, +1/2b. 2, 1, 0, 0c. 2, 2, 0, -1/2d. 2, 0, 1, -1/2 e. 2, 0, 2, +1/2
Which of the following set of quantum numbers (ordered n, ℓ, m  ℓ, ms) are possible for an electron in an atom? Check all that apply.a. 5, 3, 0, 1/2b. 2, 1, 0, 1/2c. 3, 1, 0, -1/2d. 2, 1, 0, 1e. 2, 1, -2, 1/2f. 3, 4, 0, 1/2g. 5, 3, 4, 1/2h. -1, 0, 0, -1/2
Part AWhat is the only possible value of ml for an electron in an s orbital?Express your answer numerically.Part BWhat are the possible values of m l for an electron in a d orbital?Express your answer numerically with sequential values separated by commas.Part CWhich of the following set of quantum numbers (ordered n, l, m l, ms) are possible for an electron in an atom? 
Which one of the following statements is false?a. If an electron quantum number n=2, it may be a p sublevel.b. If an electron has ℓ=1, it must be in a  p sublevel.c. Two electrons in the same atom may have quantum numbers, n , l , mℓ , ms of 2,1,-1,½, and 2,-1,- 1,½.d. Two electrons in the same atom may  not have quantum numbers of 2,1,-1,-½ and 2,1,-1,-½.e. If an electron has n=1, it must be in an s orbital
Which of the following set of quantum numbers (ordered n,l,ml,ms) are possible for an electron in an atom? Check all that apply.a. 3, 4, 0, 1/2b. 3, 2, 0, -1/2c. 3, 2, 2, -1/2d. 3, 1, 0, -1/2e. -3, 2, 2, -1/2f. 4, 3, 4, -1/2g. 2, 1, 0, 1h. 2, 1, -2, 1/2
Which of the following sets of the four quantum numbers n, l, m  l, and ms decribes one of the outermost electrons in a ground-state barium atom?a) 6, 1, 1, ½b) 6, 0, 1, -½c) 6, 0, 0, -½d) 6, 1, 0, ½e) 6, 2, 1, -½
Which of the following is a possible set of quantum numbers?
Which set of quantum numbers is correct and consistent with n = 4?(A) l = 3    m l = -3     ms = +1/2(B) l = 4    m l = +2    ms = -1/2(C) l = 2    m l = +3    ms = +1/2(D) l = 3    m l = -3     ms = +1
How many electrons can have the following quantum sets? a. In the 7 th shell of an atom (n = 7)b. n = 5, ℓ = 2c. n = 6, ℓ = 3,  m ℓ = -2d. n = 4, ℓ = 2,  m ℓ = 0 , m s = -1/2e. n = 4, m ℓ = -1f. n = 5, m ℓ = 0 , m s = 1/2g. n = 9, ℓ = 4, m s = -1/2h. n = 2, m s = 1/2
Each of the following sets of quantum numbers gives information on a specific orbital. Find the error in each. a)  n = 4, l = 0 , m l = 1, m s = -1/2b)  n = 5, l = 2 , m l = - 1, m s = 1c)  n = 7, l = 7, m l = - 5, m s = -1/2d)  n = 22, l = 5, m l = - 6, m s = 1/2
Fluorine can gain an electron to become fluoride (F−). What is the quantum number (following the numbering conventions) that describes the electron that was gained by fluorine.(a) n = 2,  ℓ  = 0, m ℓ  = 1, ms = -1⁄2(b) n = 2, ℓ = 1,  m ℓ  = 0, ms = -1⁄2(c) n = 3, ℓ = 1, m ℓ = 1, ms = +1⁄2(d) n = 2, ℓ = 1,  m ℓ  = 1, ms = -1⁄2(e) n = 2, ℓ = 1,  m ℓ  = -1, ms = -1⁄2
Which of the following represents a set of quantum number for valence electron of Chlorine?A. (3,1,0,-1)B. (3, 2, 0, -1/2)C. (3,0,2, 1/2)D. (3,1,-1, -1/2)E. (3,1,0,0)
How many of the following statements are false?I. The principal quantum number n is related to the size of an orbital.II. s, p, d, f  represent orbitals with different azimuthal quantum numbers.III. The magnetic quantum number can have values of +½ or -½.IV. The spin quantum number is related to the orientation of an orbital.V. The electron density at a point is proportional to Ψ 2 at that point.A. 0B. 1C. 2D. 3E. 4
Which of the following is not a permitted combination of quantum numbers?1. n = 4, ℓ = 2, mℓ = 1, m s = 1/22. n = 3, ℓ = 0, mℓ = 0, m s = 1/23. n = 4, ℓ = 3, mℓ = 3, m s = − 1/24. n = 2, ℓ = 1, mℓ = −2, m s = 1/25. n = 3, ℓ = 0, mℓ = 0, m s = − 1/2
 List all the quantum numbers for each of the 9 electrons in fluorine. n l ml ms.
What are the possible quantum numbers for the last electron in zinc?n = ___________l =  ___________ml =  __________ms = ___________