Quantum Numbers
There are four quantum numbers: n, l, ml, and ms. Together they tell you the location of a particular electron. When referring to certain elements, we typically use the four quantum numbers to explain where the last electron is.
n - the principal quantum number
This tells us which energy level the electron is in. The period on the periodic table tells us this as well. n can have any whole number value from 1 to infinity. Today's periodic table has 7 energy levels - so this is as far as we will go in this class.
l - Angular momentum quantum number
This tells us what shape an orbital holds. We are concerned with the first four shapes - s, p, d, and f. S is spherical and has the quantum number 0. P is a dumbbell and has the quantum number 1. D is the clover shape and has the quantum number 2. F has the most complicated shape - flower like - and has the quantum number 3.
ml - Magnetic quantum number
This tells us the specific orbital the electron is in (also referred to as orientation of the orbital). The s orbital is spherical so can only have one orientation - the number is 0. The p shape can have three different orbitals: -1, 0, 1. The d shape has 5: -2, -1, 0, 1, 2. And the f shape has 7: -3, -2, -1, 0, 1, 2, 3. Remember electrons will go into an empty orbital before they match up with an electron already in an orbital. Any given orbital can only hold two electrons.
ms - spin quantum number
This tells us...well... the spin of the electron. That is, what direction it is going because any two electrons in the same orbital must have opposite spins. This number can be +1/2 or - 1/2. The first electron in an orbital will have the positive, the second will have the negative.
Together these four quantum numbers can tell us where a given electron is located in an atom.
n - the principal quantum number
This tells us which energy level the electron is in. The period on the periodic table tells us this as well. n can have any whole number value from 1 to infinity. Today's periodic table has 7 energy levels - so this is as far as we will go in this class.
l - Angular momentum quantum number
This tells us what shape an orbital holds. We are concerned with the first four shapes - s, p, d, and f. S is spherical and has the quantum number 0. P is a dumbbell and has the quantum number 1. D is the clover shape and has the quantum number 2. F has the most complicated shape - flower like - and has the quantum number 3.
ml - Magnetic quantum number
This tells us the specific orbital the electron is in (also referred to as orientation of the orbital). The s orbital is spherical so can only have one orientation - the number is 0. The p shape can have three different orbitals: -1, 0, 1. The d shape has 5: -2, -1, 0, 1, 2. And the f shape has 7: -3, -2, -1, 0, 1, 2, 3. Remember electrons will go into an empty orbital before they match up with an electron already in an orbital. Any given orbital can only hold two electrons.
ms - spin quantum number
This tells us...well... the spin of the electron. That is, what direction it is going because any two electrons in the same orbital must have opposite spins. This number can be +1/2 or - 1/2. The first electron in an orbital will have the positive, the second will have the negative.
Together these four quantum numbers can tell us where a given electron is located in an atom.