Quantum numbers and electron Configurations Part 1

Summary

This 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

00:00

🔢 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.

05:00

🌐 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.

10:02

🚫 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.

Keywords

💡Quantum Numbers

Quantum numbers are a set of numbers that describe the state of an electron in an atom. They are like addresses that help us understand where electrons are most likely to be found within an atom. In the video, quantum numbers are used to explain the different energy levels and sublevels that electrons can occupy.

💡Principal Quantum Number

The principal quantum number, denoted by the symbol 'n', represents the main energy level of an electron. It is a whole number that starts from 1 and increases with each successive energy level. The video explains that n can take on values like 1, 2, 3, etc., correlating to the rings of the Bohr model.

💡Sublevels

Sublevels, also known as subshells or orbitals, are subdivisions within the principal energy levels. They are represented by letters such as 's', 'p', 'd', and 'f'. The video script describes how each principal energy level contains at least one s sublevel and how additional sublevels like p, d, and f appear as the energy level number increases.

💡Angular Momentum Quantum Number

The angular momentum quantum number, represented by the lowercase letter 'l', defines the shape of the sublevel or orbital. The video mentions that instead of using numbers, letters are used to represent these sublevels, such as 's' for a spherical shape, 'p' for dumbbell shapes, and so on.

💡S Orbital

An s orbital is a type of sublevel that has a spherical shape. The video script explains that within each principal energy level, there is at least one s sublevel. For example, the first principal energy level has an s orbital, and the second and third levels have additional p and d orbitals, respectively.

💡P Orbital

A p orbital is a sublevel with a dumbbell shape and is associated with the angular momentum quantum number 'l' equal to 1. The video mentions that for principal energy levels greater than one, there are three p orbitals oriented along the x, y, and z axes.

💡D Orbital

D orbitals are more complex sublevels with five different shapes, corresponding to the angular momentum quantum number 'l' equal to 2. The video script uses the example of the third principal energy level, which includes d orbitals that are larger and more spread out than s or p orbitals.

💡F Orbital

F orbitals are the most complex type of sublevel, with seven different shapes, and are associated with the angular momentum quantum number 'l' equal to 3. The video script mentions that these orbitals are too complicated to draw and are found in higher energy levels.

💡Electron Configuration

Electron configuration refers to the distribution of electrons in an atom's orbitals. The video script discusses how to use quantum numbers to write electron configurations for elements, following the rules that no more than two electrons can occupy the same orbital and that energy increases across the orbitals.

💡Energy Levels

Energy levels are the different layers in which electrons reside in an atom, and they increase in energy as one moves away from the nucleus. The video script uses the principal quantum number 'n' to explain the progression of energy levels and how electrons move to higher energy levels when they gain energy.

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