What are Isotopes?

Summary

This video explains isotopes, focusing on how they are variations of the same element with identical atomic numbers but different mass numbers due to differing numbers of neutrons. It highlights that isotopes share the same chemical properties but differ in their nuclear properties. Through examples like carbon-12 and carbon-13, the video teaches how to identify isotopes using atomic symbols and quizzes viewers to reinforce understanding of key concepts such as atomic number, mass number, and the composition of isotopes.

Takeaways

• 🔬 Isotopes are variants of the same chemical element with different mass numbers due to a varying number of neutrons.
• 📊 The atomic number (Z) identifies the element and is the same for all isotopes of that element, representing the number of protons.
• 🧬 Isotopes have identical chemical properties because they are composed of the same element and have the same atomic number.
• ⚛ Isotopes differ in their nuclear properties due to the different number of neutrons, which can lead to varying stability and radioactivity.
• 📖 The mass number is the sum of the protons and neutrons in an isotope's nucleus.
• 📚 The periodic table displays the atomic number of elements, which helps in identifying the element based on its atomic number.
• 🔢 To calculate the number of neutrons in an isotope, subtract the atomic number from the mass number.
• 🌐 Isotopes with the same atomic number but different mass numbers are isotopes of each other, sharing the same chemical element.
• 🚫 Isotopes cannot be of different elements; they must be composed of the same element to be considered isotopes.
• 📝 Writing an atomic symbol involves placing the mass number at the top and the atomic number at the bottom, followed by the element's symbol.
• 💡 To determine the element from the atomic number, reference the periodic table to find the element with the corresponding atomic number.

Q & A

What is an isotope?

An isotope is a variant of a chemical element that has the same number of protons (same atomic number) but a different number of neutrons, leading to a different mass number.

How do isotopes of an element differ from each other?

Isotopes of an element differ in their mass numbers due to different numbers of neutrons in their nuclei.

Do isotopes have different chemical properties?

No, isotopes have the same chemical properties because they have the same number of protons and electrons, which determine chemical reactivity.

What causes isotopes to have different nuclear properties?

Isotopes have different nuclear properties because of the different numbers of neutrons in their nuclei, which can affect the stability and radioactivity of the atom.

How do you calculate the number of neutrons in an isotope?

The number of neutrons in an isotope is calculated by subtracting the atomic number (number of protons) from the mass number (sum of protons and neutrons).

Are isotopes with different atomic numbers of the same element?

No, isotopes must have the same atomic number, meaning they must be the same element. If the atomic numbers differ, they are different elements.

What information is needed to write the atomic symbol of an isotope?

To write the atomic symbol of an isotope, you need the element’s atomic number, mass number, and the element’s symbol from the periodic table.

Why is carbon-12 more common than other carbon isotopes?

Carbon-12 is more common because its mass number of 12 corresponds to a stable configuration with six protons and six neutrons, making it the most abundant form of carbon.

Can isotopes of the same element have the same mass number?

No, isotopes of the same element cannot have the same mass number. They must differ in mass number due to different numbers of neutrons.

Why is it important to know the number of neutrons in an isotope?

Knowing the number of neutrons is important because it determines the isotope’s mass number and influences its nuclear properties, including stability and radioactivity.

Outlines

00:00

🔬 Understanding Isotopes: Definition and Basic Properties

This paragraph introduces isotopes by comparing carbon-12 and carbon-13, illustrating that isotopes are variants of the same element with the same chemical properties due to identical atomic numbers. The atomic number (Z) is defined as the number of protons, which is constant for a given element and determines its identity. The mass number is the sum of protons and neutrons, and differences in mass numbers among isotopes are attributed to varying numbers of neutrons in the nucleus. The paragraph also clarifies that isotopes share the same chemical behavior but can have distinct nuclear properties, including radioactivity.

05:02

📚 Isotope Identification and Symbol Representation

The second paragraph delves into the criteria for identifying isotopes and how to represent them with atomic symbols. It emphasizes that isotopes must have the same atomic number, indicating they are composed of the same element. The paragraph provides examples to demonstrate how to calculate the mass number from the number of protons and neutrons and how to identify the element using the periodic table. It also corrects common misconceptions about isotopes, such as the belief that they share the same mass number or number of neutrons, and clarifies that they have identical chemical properties but can vary in nuclear behavior.

10:02

📖 Isotope Quiz: Testing Knowledge on Isotope Characteristics

The final paragraph presents a true or false quiz to reinforce the understanding of isotopes. It tests knowledge on fundamental concepts such as the atomic number being equal to the number of protons, the mass number being the sum of protons and neutrons, and the composition of isotopes from the same element with the same atomic number. The quiz also addresses misconceptions, such as isotopes having the same mass number or number of neutrons, and having different chemical properties, which is false. The correct answer is provided for each statement, emphasizing the distinction between isotopes' nuclear properties and their uniform chemical behavior.

Keywords

💡Isotope

An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons in its atomic nucleus. In the video, isotopes are the central theme, exemplified by carbon-12 and carbon-13, which are isotopes of carbon with different mass numbers due to a differing number of neutrons. The concept is crucial for understanding the video's exploration of atomic structure and properties.

💡Mass Number

The mass number of an isotope is the total number of protons and neutrons in its nucleus. It is a key concept in the video, used to distinguish between isotopes of the same element, such as carbon-12 and carbon-13, where the difference in mass number is due to a different number of neutrons.

💡Atomic Number

The atomic number, denoted by 'Z', is the number of protons in an atom's nucleus and uniquely identifies an element. In the video, the atomic number is consistently six for carbon, regardless of whether it's carbon-12 or carbon-13, emphasizing that isotopes of the same element have the same atomic number.

💡Nucleus

The nucleus of an atom is the central part of the atom, containing protons and neutrons. The video explains that the difference in isotopes lies within the nucleus, where the number of neutrons varies, affecting the mass number and nuclear properties of the isotopes.

💡Neutron

A neutron is a subatomic particle found in the nucleus of an atom, with no electrical charge. The video script uses neutrons to explain the difference in mass numbers between isotopes, such as the difference between six and seven neutrons in carbon-12 and carbon-13, respectively.

💡Chemical Properties

Chemical properties are the characteristics that define how an element reacts with other elements. The video clarifies that isotopes share the same chemical properties because they are composed of the same element, despite having different mass numbers and neutron counts.

💡Nuclear Properties

Nuclear properties refer to the characteristics of an atom's nucleus, including its stability and radioactivity. The video script distinguishes between isotopes based on their nuclear properties, which can vary due to differences in the number of neutrons, leading to different behaviors such as radioactivity.

💡Element

An element is a pure substance made of only one type of atom. The video uses the term 'element' to describe the fundamental building block of matter, emphasizing that isotopes are always composed of the same element but differ in their neutron count.

💡Periodic Table

The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number. The video script refers to the periodic table to identify elements based on their atomic number, such as nitrogen with an atomic number of seven.

💡Atomic Symbol

An atomic symbol is a one- or two-letter abbreviation that represents an element on the periodic table. The video script instructs viewers on how to write atomic symbols for isotopes by using the atomic number and mass number, as illustrated with the example of nitrogen, symbolized as ^{15}N.

💡Quiz

A quiz is a form of assessment designed to test knowledge on a particular subject. The video script includes a quiz to reinforce the viewer's understanding of isotopes, with true or false questions about atomic numbers, mass numbers, and the properties of isotopes.

Highlights

Isotopes are variants of the same element with different mass numbers.

Carbon-12 and Carbon-13 are used as examples to illustrate isotopes.

Isotopes have identical chemical properties due to the same atomic number.

The mass number represents the sum of protons and neutrons in an isotope's nucleus.

The atomic number identifies the element and is consistent across isotopes of that element.

Isotopes differ in their nuclear properties due to varying numbers of neutrons.

Some isotopes are radioactive, emitting radiation, while others are not.

The number of neutrons in an isotope can be found by subtracting the atomic number from the mass number.

Isotopes must have the same atomic number to be considered isotopes of each other.

Different mass numbers among isotopes indicate different numbers of neutrons.

Isotopes share the same chemical reactivity despite having different nuclear behaviors.

The periodic table is used to identify elements based on their atomic numbers.

Writing atomic symbols for isotopes involves using the mass number, atomic number, and element name.

The most common isotope of an element may not be the only isotope; other isotopes can exist.

Unstable isotopes with only one neutron, such as the hypothetical Fluorine-10, are possible.

A quiz is provided to test knowledge on isotopes, including true or false questions about their properties.

Isotopes do not differ in the number of protons, which is a key point in their definition.

The video concludes with a summary of the key facts about isotopes to remember.

Transcripts

so what exactly is an isotope

in this video

we're going to talk about isotopes

now instead of giving you a definition

i'm going to illustrate it with an

example

consider carbon-12

and carbon 13.

these two substances are isotopes of

each other

as you can see isotopes are composed of

the same element

both of these atoms

they're carbon atoms so chemically

speaking they react the same way

now the number that you see here is the

mass number

carbon 12 has an atomic number of six

the same is true for carbon 13.

the atomic number of an element

identifies the element

so carbon will always have an atomic

number of six

so z represents the atomic number

so when you look at a periodic table

you're going to see two numbers

the smaller of the two numbers is the

atomic number and the larger of the two

values is the mass number

so isotopes they're composed of the same

element in this example

both isotopes are elemental carbon if

the elements are different then you

don't have an isotope

isotopes also have the same atomic

number because the element is the same

however

they differ

in

the mass number

so isotopes will always have different

mass numbers now the question is why

the answer lies in the nucleus of the

atom

the nucleus

of

an isotope or of two isotopes

are different

it's not the same

the atomic number tells us the number of

protons

the mass number

is the sum

of the protons and the neutrons

so both carbon 12 and carbon 13

have an atomic number of six

so therefore the number of protons is

six

the number of electrons will be the same

it's six as well

for a neutral atom the number of protons

and electrons are equal to each other

now the number of neutrons to find it

subtract the mass number by the atomic

number 12 minus 6 is 6.

so carbon 12 has six neutrons

carbon-13 has 13-6 or seven neutrons

so the reason why the mass number is

different is because the number of

neutrons

are different and so isotopes they have

the same chemical properties because

they're composed of the same elements

but they exhibit different nuclear

properties

some isotopes

are not active on a nuclear level while

others

emit radiation some are harmless some

are harmful so the nuclear properties

are different but their chemical

properties are the same

so if you're studying for a test here

are some key facts that you want to

remember

isotopes

are always composed of

the same element

so remember that the element can't be

different it has to be the same element

isotopes are similar to each other

in that

they have the same atomic number

and as a result they share the same

number of protons

isotopes differ from each other

because their mass numbers are different

they have different mass numbers and

also

they have different numbers of neutrons

so remember that isotopes they have the

same number of protons same atomic

number and they're composed of the same

element but they have different mass

numbers and different numbers of

neutrons

and isotopes share the same chemical

properties but they differ

in nuclear properties their nucleus

behave differently

because the number of neutrons is

different which exists in the nucleus

so those are some key ideas that you

want to keep in mind when dealing with

isotopes

so let's work on a few questions

that will test your knowledge on

isotopes

so let's look at substance a

and substance b

now just because the letters are

different

doesn't mean that the elements are

different

so a and b could represent the same

element or they could represent a

different element use the numbers to

figure out

which is the case so let's say substance

a

has an atomic number of 12

and a mass number of 29 and substance b

has an atomic number of 13 and the mass

number of 30.

these two substances are the isotopes of

each other

the answer is

they're not isotopes of each other

isotopes must have the same atomic

number which means they must be

composed of the same element because the

atomic number is different

the elements are different and so these

are not isotopes of each other

now let's compare substance c and

substance d

let's say substance c has an atomic

number 15 and a mass number 32

and substance d has an atomic number 15

and a mass number of 33.

are these two substances are they

isotopes of each other

the answer is yes

they share the same atomic number which

means that substance c and d are

composed of the same type of element

however

the math number is different and so

therefore the number of neutrons will be

different

so substance c and d are isotopes of

each other

now let's work on this problem i want

you to write the atomic symbol for each

situation

so if there are seven protons and eight

neutrons

how can you represent this isotope

using an atomic symbol for it

so the first thing you want to do is

find the atomic number and the mass

number

the atomic number z is always equal to

the number of protons

the mass number

is the number of protons plus the number

of neutrons

so that's going to be 7 plus eight

so the mouse number is fifteen

so whenever you're writing a symbol

you're gonna have the element

the mass number

and the atomic number

so we have a an atomic number of seven a

mass number 15.

now we need to identify the element

well how can we do that

the identity of the element depends on

the atomic number or the number of

protons

so we need to do is you need to get a

periodic table

and look for an element with an atomic

number of seven that's going to be the

smaller of the two numbers that you'll

see in the periodic table

so this has to correspond to nitrogen

nitrogen has an atomic number of seven

so this is how you can write the atomic

symbol

of an element or an isotope

if you're given the number of protons

and neutrons

so go ahead and pause the video and do

the same thing for parts b c

and d

so let's focus on part b

the atomic number as we said before is

the number of protons so z is 11

the number of neutrons is 13.

so the mass number is going to be the

number of protons plus the number of

neutrons 11 plus 13 is 24.

so using this process where we're going

to put the mass number on top the atomic

number on the bottom left

so we have an atomic number of 11 and a

mass number of 24.

so now go to the periodic table and

identify the element that has an atomic

number of 11.

this is going to be sodium

so this is the answer it's sodium 24.

the most common isotope of sodium is

sodium

23. the atomic mass of sodium is about

22.99

which means the most common isotope is

sodium 23 but there could be other

isotopes sodium 22 sodium 24.

it's just sodium 24 is not the most

common isotope

now let's move on to part c

we have an atomic number of 14 so that's

our z value

and the number of neutrons is 15.

so the mass number is going to be 14

plus 15 which is 29.

so we got a mass number of 29 and atomic

number 14. what is the element

so this has to correspond to silicon

silicon has

an atomic number of 14. so this is the

answer for part c

now let's move on to part d

the number of protons is 9 so that's z

the mass number is

10.

so what we have is ten and nine

an atomic number of nine corresponds to

fluorine

now this is a very isotope because it

means that only has one neutron so it's

not a stable form of fluorine but based

on the information we have

that's going to be the answer

so now you know how to write the atomic

symbol for an isotope

if you're given the number of protons

neutrons or the mass number

now

let's test your knowledge on facts about

isotopes so here we have a video quiz

and it's a true or false quiz so feel

free to pause the video

number one

the atomic number is equal to the number

of protons is that a true statement or

is it a false statement

this is a true statement

the number of protons will always be the

same as the atomic number

now what about number two

the mass number is the sum of the number

of protons and neutrons

that is a true statement

now what about three isotopes are

composed

of the same element

yes in our first example we dealt with

carbon-12 and carbon-13 they were both

of the same element carbon

isotopes have the same atomic number

that's also a true statement

isotopes share the same mass number

that is a false statement

isotopes have different

mass numbers

now what about number six

isotopes have the same number of

neutrons

is that true or false

this is a false statement if the mass

number is different then the number of

neutrons

will be different as well

isotopes differ in the number of protons

that's false

they have the same atomic number and the

atomic number is equal to number of

protons so therefore they must have the

same

number of protons

now what about number eight

isotopes possess different chemical

properties is that true or false

that is false because isotopes are

composed of the same element like carbon

12 and carbon 13

they have the same

chemical properties

their chemical reactivity is identical

to each other

now what about number nine

isotopes possess different nuclear

properties that is a true statement

because the number of neutrons is

different and neutrons are found in a

nucleus

the nucleus will behave differently

so therefore

isotopes have different nuclear

properties

but they share the same chemical

properties

so that's it for this video and thanks

for watching

you