Quantum numbers and electron Configurations Part 1
Summary
TLDRThis script discusses quantum numbers, essential for understanding electron locations in atoms. It introduces the principal quantum number (n), which defines energy levels, and the angular momentum quantum number (sublevels), represented by letters (s, p, d, f). Each sublevel has a distinct shape, with s being spherical, p having three dumbbell shapes, d having five complex shapes, and f having seven shapes. Electrons fill these orbitals sequentially by energy level and sublevel, with no more than two electrons per orbital. The script aims to help viewers grasp electron configurations in elements.
Takeaways
- 📊 Quantum numbers are like addresses for electrons in an atom, helping to define their position 90% of the time.
- 🔢 The principal quantum number (n) defines the principal energy level and can take whole number values starting from 1.
- 🌐 Each principal energy level corresponds to a shell in the Bohr model, with increasing energy as n increases.
- 🔤 Sublevels (subshells) are designated by letters (s, p, d, f) and are associated with different shapes of orbitals.
- 📚 S sublevels are spherical, p sublevels are dumbbell-shaped, and higher sublevels like d and f are more complex.
- 🚫 No more than two electrons can occupy any single orbital or suborbital.
- ⬆️ Electron energy increases with higher principal energy levels and more complex sublevels.
- 🔄 Electrons in s orbitals have the lowest energy, while those in p, d, and f orbitals have higher energy.
- 📚 The number of orbitals increases with the principal energy level: 1s, 2s and 2p, 3s, 3p, and 3d, etc.
- 📈 The probability of finding an electron in a certain region of an atom is defined by the shape of the orbital.
Q & A
What are quantum numbers?
-Quantum numbers are like addresses for electrons in an atom, a set of numbers and letters used to distinguish where electrons are 90% of the time.
What is the principal quantum number?
-The principal quantum number, denoted by n, represents the principal energy level of an electron and can take on whole number values such as 1, 2, 3, etc.
How does the principal quantum number relate to the Bohr model?
-In the Bohr model, each principal energy level corresponds to a ring or shell, with n=1 being the first ring, n=2 the second, and so on.
What are sublevels?
-Sublevels, also known as subshells, are subdivisions within the principal energy levels and are denoted by the angular momentum quantum number, represented by the lowercase letter 'l'.
What do the letters s, p, d, and f represent in sublevels?
-The letters s, p, d, and f represent different shapes of sublevels or orbitals: s for spherical, p for dumbbell-shaped, d for more complex shapes including a 'donut' shape, and f for even more complex shapes.
How many electrons can occupy a single sublevel?
-No more than two electrons can occupy any single sublevel or orbital.
How does energy relate to the position of electrons in orbitals?
-Energy increases as electrons move to higher principal energy levels or more complex sublevels. Electrons in lower energy levels or simpler orbitals have less energy.
What is the significance of the probability model mentioned in the script?
-The probability model is used to visualize where electrons are likely to be found within an atom, represented by different shapes corresponding to s, p, d, and f orbitals.
How many different types of orbitals are there in the third principal energy level?
-The third principal energy level contains an s orbital, three p orbitals, and five d orbitals.
What is the maximum number of orbitals in a principal energy level?
-The maximum number of orbitals in a principal energy level increases with the level number: 1 for n=1, 4 for n=2 (1s, 3p), 9 for n=3 (1s, 3p, 5d), 16 for n=4 (1s, 3p, 5d, 7f), and so on.
How does the size of the orbitals change with the principal energy level?
-The size of the orbitals increases with the principal energy level, meaning that higher energy levels are further from the nucleus.
Outlines
🔢 Understanding Quantum Numbers
The paragraph introduces quantum numbers as essential identifiers for electrons within an atom, akin to an address. The principal quantum number, denoted by 'n', is highlighted as the starting point for understanding electron locations. It can take integer values starting from 1 upwards, correlating with the rings of the Bohr model. Sublevels, or subshells, are introduced with the angular momentum quantum number, represented by 's', 'p', 'd', and 'f' orbitals, each with distinct shapes. The paragraph emphasizes the complexity of electron distribution within an atom, with each principal energy level containing at least one sublevel, and higher energy levels accommodating more varied sublevels.
🌐 Visualizing Electron Orbitals
This section delves into the visualization of electron orbitals using the probability model, contrasting it with the Bohr model. It explains that while s orbitals are spherical and can contain two electrons, p orbitals are dumbbell-shaped and there are three of them oriented along the x, y, and z axes. The paragraph further discusses how the complexity of orbital shapes increases with higher energy levels, introducing d orbitals with five shapes and f orbitals with seven. It emphasizes the increasing energy requirement for electrons to occupy these more complex orbital arrangements.
🚫 Electron Configuration Rules
The final paragraph outlines the rules for electron configurations within orbitals. It states that no more than two electrons can occupy a single orbital, and this rule applies to all types of orbitals (s, p, d, f). The paragraph also discusses the increase in energy as electrons move to higher principal energy levels or to orbitals of higher complexity (e.g., from s to p to d). The concept is applied to the electron configurations of elements, with a focus on the first 36 elements, emphasizing the importance of understanding these rules for predicting electron distribution in atoms.
Mindmap
Keywords
💡Quantum Numbers
💡Principal Quantum Number
💡Sublevels
💡Angular Momentum Quantum Number
💡S Orbital
💡P Orbital
💡D Orbital
💡F Orbital
💡Electron Configuration
💡Energy Levels
Highlights
Quantum numbers are like addresses for electrons in an atom.
Principal quantum number (n) represents the principal energy level.
n can take on whole number values corresponding to energy levels in the Bohr model.
Sublevels (subshells) are designated by the angular momentum quantum number (l).
Sublevels are represented by letters: s, p, d, f for different shapes.
s sublevel represents a spherical region where electrons are found 90% of the time.
Principal energy level 2 contains s and p sublevels.
p sublevels have three orbitals oriented in the x, y, and z directions.
Higher energy levels contain more sublevels: s, p, d, and f.
D sublevels have five different shapes, including one with a 'donut' shape.
F sublevels are the most complex with seven different shapes.
No more than two electrons can occupy any single suborbital.
Energy increases as you move to higher principal energy levels or more complex sublevels.
Electrons in s orbitals have lower energy than those in p or d orbitals.
The system of quantum numbers helps to write electron configurations for elements.
Electron configurations will be filled in for elements 1 through 36 as an exercise.
Transcripts
today we're going to talk about quantum
numbers also known as the address for
any electron inside of an
atom so quantum numbers are just like
the address for mailing something to
somebody's house it's a set of numbers
and letters that we're going to use to
distinguish where the electrons are 90%
of the time in an
atom so we'll start with What's called
the principal quantum number also known
as the principal energy
level and the lowercase n stands for the
principal quantum number and the number
n can have certain values most of which
you are familiar with for example and
could take on the value of
one or it could be
two uh then there's the very familiar
three also
four five and so
forth principal energy level or
principal quantum number can take on
these whole number values 1 2 3 4 5 and
so forth all the way
up what does that translate to what does
that
mean if you look look at the bore model
you can
see that the first principal energy
level is the very familiar first ring of
the bore model Nal 2 second ring and Nal
3 be the third ring and so forth you
could add
another which would be the fourth
principal energy
level and
n equals
4 and these are familiar to you I think
from studying the Bor mod okay so
electrons could reside in any one of
these principal energy levels and that
sounds uh very simple it does however
get a little more complicated because
within those levels there are what we
call suble
levels and those have a slightly
different
designation now well use this uh
lowercase cursive L to stand for these
Su levels okay and this is what's called
the angular momentum quantum number but
you just need to understand it as a su
okay so we'll just write
[Music]
suev and that's what you have to
remember now there are numbers that go
with this but we're not going to use the
numbers that are associated with this
we're going to use letters instead and
you'll see how this all comes together
later but for now
what we need to understand is that there
are certain letters that are going to be
associated with each of these Su
levels for example
s it's a lowercase s stands for a su
that has a particular shape and you can
look at the pictures in your book and
I'll show you what I'm talking
about with the probability
model the shape designated by an s suble
I think I'd like to use blue on that to
stay
consistent there we
go here's where the probability comes in
90% of the time you will find an
electron in an s
suev in some region defined by a
sphere now s doesn't stand for
sphere but that's what it means you will
find this electron somewhere in area
defined by a
sphere
okay every principal energy level has at
least one suev but as we get higher and
higher in energy you find more Su levels
so for
example the principal energy level or
principal quantum number two not only
does it contain s suble
uh often you call these
orbitals but it also
contains what we call P orbitals or P
sublevels these are lowercase P's in
case you're
wondering and there are three of
those now what does that look like well
it's too complicated to draw on the bore
model so we're going to go to our
probability model and show you what that
might look like the S
orbital in the second princial energy
level is
bigger and I'm not going to fill in the
whole thing but you get the idea that an
electron could be somewhere within that
region it's a little further out from
the
nucleus but an electron could also
reside in one of these so-called
P
orbitals which have a different
shape so there's one in the Y
Direction X
Direction and if you can imagine this is
threedimensional
in the Z Direction so you can see now
it's getting more
complicated and these electrons can be
found in different regions of the atom
defined by these shapes and we're just
using the letters to tell us which shape
orbital the electrons might be found in
so you have these
s the third principal energy level can
have you may have guessed three
different sus or three different types
of
orbitals an S
orbital
again three of these so-called P
orbitals
and a certain number of what we call D
orbitals there are five possible D
orbitals now it's going to get really
complicated you can't draw it on here
but this third principal energy
level would have
again an S
orbital much larger than the second
principal energy level so the electrons
might be found somewhere in this
region it could have P
orbitals and electrons found within the
region defined by these P
orbitals same orientations X Y and Z but
notice it's
bigger
and you can see how complicated this is
drawing is getting and that's why we're
going to be using the numbers or
the little shorthand to designate where
the electrons are because this is just
too complicated to show where they
actually
are and the D orbitals are more
complicated you can use your book to see
the five different shaped D orbitals uh
but my favorite of
course is the one that has the donut in
the
middle
see if I can draw
that and so the electrons might be found
somewhere in the region defined by this
oddly shaped dumbbell SL
donut and you can imagine that as you
progress through our little system here
it takes more energy to get into these
more complicated Arrangements of
electrons
okay
the fourth principal energy
level again there is an S orbital
involved a little more energy and the
electrons could reside in any one of
three different P orbitals but again
those are going to be further from the
nucleus there are also five so-called D
orbitals and
you may have
guessed even more complicated F orbitals
and how many do you think there are
those seven so-called F orbitals and
those are just way too complicated for
me to draw so not I'm going to
try but you could look those up on the
internet and progresses from there the
fifth energy level principal energy
level has five different orbitals or Su
lels but we probably won't be using many
of
those so now we have the basics of the
system of writing quantum numbers or
what we're going to do which is writing
electron
configurations so there's a couple
things we have to remember when we're
doing this
first thing is
that you can have no more than two
electrons at any
suev or
orbital and my pen is dying here but I'm
going to do the best I
can no more
than two
electrons in any
suborbital uh any orbital that means in
any s you can have two electrons that's
it in any P you can have only two
electrons that's it but the total here
would
be six total electrons there okay so you
can have no more than two electrons in
any
one suev or
orbital and this is where you're going
to get the numbers that you're familiar
with eight in the first or sorry
two in the first
row eight in the second
row and so forth that's where some of
these numbers are going to come into
play the other thing we have to remember
is
energy I'll stick with
red
energy increases as we move across our
little chart
here the energy of the electron
increases so an electron that is in the
first principal energy level has the
lowest amount of energy if you add
energy to that electron it will jump up
to maybe the second principal energy
level in order to be in a higher
principal energy level the electron has
to have more
energy but this works down our little
chart as well
if an electron is in an S orbital and
gains energy it can move up into a p
orbital so as we move down the chart
these more complicated sus require more
energy for the electron in order to be
in those orbitals or another way of
thinking about it to be found within the
region defined by those
orbitals if you only have a smaller
amount of energy you could maybe in one
of the P
orbitals and if you have more
energy you might find yourself or the
electron might find itself in a d
orbital in a more complicated
shape now we're going to use these
numbers and letters to designate exactly
where the electrons are in a few
elements or atoms of a few elements and
then you are going to fill in the
electron configurations for elements 1
through 36 so let me get you
started
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