O Level Chemistry: Difference between Atom, Molecule & Particle

24 Feb

Posted by: sean in: Chemistry Notes & Tips

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Can you differentiate between Atom, Molecule & Particle? I received an enquiry from a subscriber to SimpleChemConcepts.com yesterday and i realized that many students have misconception of the different definitions given to them.

When we say Avogadro’s Number states that there are 6 x 10^23 particles for 1 mole of substances, the “particles” is actually a general term.

“Particles” can mean atoms (He gas atoms), molecules (H2 gas, N2 gas molecules), ionic substances (NaCl ionic salt) or even the ions itself (Chloride Cl- anions, Mg2+ cations).

Do not confuse between this “Particle” as the other “Sub-atomic Particle” that is mentioned in the topic of Atomic Structure. The “Sub-atomic Particle” refers to the PEN – Proton, Electrons & Neutrons. These “Sub-atomic particles are smaller than the atoms themselves.

By the way,

Atom is defined as the the smallest component of an element having the chemical properties of the element. Example, any of the elements you see on the periodic table exist as atom.

Molecule is defined as a group of two or more atoms held together by covalent bonds. When atoms combine by sharing electrons, molecules are formed. Example, H20 molecules, CO2 molecule, Cl2 gas molecule.

Hope the above explaination helps. Do leave your comments in the “comment” section below.

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28 Responses

Gary
25|Feb|2008 1

So lets say if they ask:

How many atoms are there in 1 mol of NaCl

It would simply be (6*10^23)(1)(2)?

Reply
sean
25|Feb|2008 2

You are absolutely spot on!

1 mol contains (6*10^23) NaCl ionic compounds.

Since NaCl consists of 2 atoms, Na and Cl atom,

Therefore total no. of atoms = (6*10^23)(1)(2)

Cheers

Reply
Jen
29|Feb|2008 3

Hey, what is the difference between compounds and molecules then?

Reply
Elaine Reply:
February 8th, 2009 at 7:22 am
compunds are made up of molecules I think. For example, water is a compound, and it’s consisted of many many water molecules

Reply
sean
04|Mar|2008 4

Very good question Jennifer.

First, you would need to know the difference between Elements, Compounds &
Mixtures. When 2 or more elements come together without any chemical reactions,
then a Mixture is formed. When you have 2 or more elements that comes
together in a chemical reaction (light and/or heat given off), they formed a new
substance that have different properties from those elements they are formed,
we called these substance as Compounds.

Compounds can be:
a) Ionic Compound – formed by Ionic Bonding e.g. NaCl, MgSO4
b) Covalent Compound – formed by Covalent Bonding e.g. Water, Carbon Dioxide

Hope this helps.

Reply
sandy
12|Apr|2008 5

means that a compound could also be a molecule..
and that molecule are made of same elements
while compound could be made up of different elements?

Reply
sean
13|Apr|2008 6

Hi Sandy,

Yes. You are spot on.

Molecules are defined as a group of 2 or more atoms that are held together by
covalent bonds, which can be:

A) Molecules of Elements – made up of same elements e.g. Cl2, H2, O2, N2,etc

B) Molecules of Compounds – made up of different elements e.g. CO2, H2O, etc

Hope this helps.

PS: You can become a subscriber of ths Chemistry Blogsite by signing up at:
http://www.simplechemconcepts.com/balancechemicalequations.html

Rgds,
Sean
Author of SimpleChemConcepts.com

Reply
Maureen
19|Aug|2008 7

I totally understand. Thank you so so much. Godspeed. I love you

thank you.

hope you reply.

bye.

Reply
sean Reply:
December 15th, 2008 at 11:38 am
Hi Maureen,

I am glad you have learned something about to improve your grades in Chemistry.

Rmbr that Chemistry is all about basic essential concepts. You need to have a strong foundation of these essential concepts in order to score well for application topics later on.

Check out other questions posted and discussed in this blog, by selecting the “Question and Answer” under the Category Box on the RHS.

If you have a specific topic that you would like to revise on, enter the Topic Keywords in the “Search for Chemistry Topics” field on the RHS.

All The Best To Your Academic Success in Chemistry,
Sean
Master Trainer
Author

Reply
Emma
01|Sep|2008 8

Is molecule interchangeable with compound, then?

Reply
sean Reply:
December 15th, 2008 at 11:42 am
Hi Emma,

Apparently, different books present them in different ways. It is confusing if you do not have a coach or teacher to guide you through those assessment or textbooks.

In general, “Molecule” is NOT ” Compound”.

Refer to my earlier comment above.

Compound can refer to both Ionic substances as well as Covalent substances.

Molecule is only associated to Covalent substances.

Hope this makes it even clearer for you.

Cheers
Sean
Master Trainer
Author

Reply
Lorna
21|Nov|2008 9

Thank you very much for explaining the difference between a molecule, atom and particle. I have always been stuck on which one to use (especially when it comes to molecules/particles) so now I know!
Lorna.

Reply
sean Reply:
December 15th, 2008 at 11:42 am
Hi Lorna,

I am glad you are learning something here.

Rmbr that Chemistry is all about basic essential concepts. You need to have a strong foundation of these essential concepts in order to score well for application topics later on.

Check out other questions posted and discussed in this blog, by selecting the “Question and Answer” under the Category Box on the RHS.

If you have a specific topic that you would like to revise on, enter the Topic Keywords in the “Search for Chemistry Topics” field on the RHS.

All The Best To Your Academic Success in Chemistry,
Sean
Master Trainer
Author

Reply
kimberly
27|Jan|2009 10

2 quistions….first how many ions are in KCl? and second….what do the attractions between H20 and chloride ions look like? i hope you can help me…thanks

Reply
sean Reply:
February 9th, 2009 at 5:25 pm
Hi Kimberly,

They are 2 ions in KCl, namely K+ and Cl- ions

KCl is an ionic compound and there are electrostatic forces of attraction between the positive and negative ions. This attraction is known as Ionic Bonding.

H2O is a covalent molecule. There is covalent bonding between the H and O atoms. But between the H2O molecules, they are held together weekly by weak van der Waals forces.

Hope this is helpful to you.

PS: Where are you from? Just started to learn Chemistry? Sec 3?

To Your Academic Success in Chemistry,
Sean
Master Trainer
Author

Reply
riya
08|May|2009 11

whats the difference between 2O and O2

Reply
sean Reply:
June 2nd, 2009 at 2:11 am
Hi riva,

When we say O2 – it refers to the molecular compound Oxygen Gas.

For 2O – it shows that there are 2 Oxygen Atoms that are going to react with other substances.

Hope this information helps.

PS: Do try out other questions in this blog

To Your Academic Success in Chemistry,
Sean Chua
Master Trainer @ SimpleChemConcepts.com
Author of Up Your Chemistry Grades Now! book

Reply
Nurul
12|Jul|2009 12

hye, sean. i just started my chemistry class. can u please explain to me what are the differences btween atoms, molecules and ions?

thank you.

Reply
sean Reply:
September 8th, 2009 at 10:27 pm
Very valid question for those just started on learning Chemistry.

Definition as follows:

ATOMs
- The smallest particle of an Element that has the chemical properties of that element

MOLECULEs
- A molecule is a group of two or more atoms that are chemically combined together

IONs
- An ion is basically a charges particle.
- Anion (-ve ion) are formed when an atom gain electron (s)
- Cation (+ve ion) are formed when an atom lose electron (s)

Hope this helps you in your learning.

Cheers
Sean

Reply
Nurul
12|Jul|2009 13

hye sean. anyway, sean, don’t u have any notes about the organic chemistry?

Reply
sean Reply:
September 8th, 2009 at 10:17 pm
Hi Nurul,

Over the last 18 months, i have written several blogposts on Organic Chemistry.

Do a search on the right hand side SEARCH bar with the key word “Organic Chemistry”.

All the best to your learning of chemistry,
Sean

Reply
Coty
06|Oct|2009 14

Hey, I’m doing problems in my chem class involving molecules and mols. What is the difference (if any) between a mol and a molecule? Are they the same thing?

Reply
sean Reply:
October 15th, 2009 at 12:15 pm
Hi Coty,

There are different.

The unit of measurement for atoms and molecules is the Mole. The mole is also the S.I. Unit for chemical quantity i.e. how much. The symbol for the mole is mol.

Molecule is a group of 2 or more atoms that are chemically combined together.

Hope this information helps. =)

To Your Academic Success in Chemistry,
Sean Chua

Reply
Coty Reply:
October 23rd, 2009 at 10:46 am
Thanks so much for your help! Mole and molecules always confused me but since you put it that way it makes sense now. Just to let you know I made a 94 on my college chem. exam and it was the highest in my class, so you helped a ton!

Thanks again and God bless,
Coty

Reply
sean Reply:
November 1st, 2009 at 12:03 am
Hi Coty.

I am glad to hear that.

We thank you for your encouraging words.

Feel free to drop us any comments. Cheers!
Russell
11|Oct|2009 15

Hey Sean, Element is define as a pure substance that are make up of a single type of atoms. And molecules are make up of Atoms. So doesn’t that mean that a Molecule is the same as an Element?

Reply
sean Reply:
October 15th, 2009 at 12:24 pm
Hi Russell,

This is the basic essential concepts of Chemistry that are causing some junior chemistry students some problem. In Singapore, the Sec 3s (some Sec 2s) are having the same misconceptions on these.

Molecule is NOT THE SAME as Element.

Molecules are made up of 2 or more atoms that are chemically combined together. Element is the “name” that describes the atoms, and the total number of Elements are stated in the Periodic Table.

Hope this information helps. =)

To Your Academic Success in Chemistry,
Sean Chua

Reply
Chaewoo
09|Nov|2009 16

We say that a molecule is made up of two or more atoms chemically joined together. Then it means that the atoms are from the same element? (well they can be) but then water H20 is can be a molecule and compound. How do we tell what is a molecule and what is a compound?

and what is a covalent bond?

Reply