Difference in working out relative atomic mass and relative isotopic mass?

I'm starting all the way from the beginning again and want to be precise in my notes.

I know the difference in meaning: RAM is weighted mean mass compared with 1/12th mass of carbon 12 and RIM is weighted mean mass of an isotope compared with 1/12th of the mass of an atom of carbon 12... right?

But the working out is very similar, as in they both follow the same working out method pretty much:
(x)+(x)
____
(x)+(x)

(edited 8 years ago)

Reply 1

Kvothe the Arcane

20

Someone, perhaps @charco, please correct me if I'm wrong but I doubt you'd have to work out the relative isotopic mass. The RIM is given to you to find the relative atomic mass.

I hope this helps

Reply 2

Someoneanyone

OP

1

Original post by Kvothe the arcane

Someone, perhaps @charco, please correct me if I'm wrong but I doubt you'd have to work out the relative isotopic mass. The RIM is given to you to find the relative atomic mass.

I hope this helps

THANK YOU THANK YOU THANK YOU!!!!!!!!!!!!!!!!!!!!
i can't thank you enough! I wouldn't continue my notes until I didn't have an answer! I checked my past exam questions and like you said I'd been given the RIM and then asked to work out the RAM.

Original post by Kvothe the arcane

Someone, perhaps @charco, please correct me if I'm wrong but I doubt you'd have to work out the relative isotopic mass. The RIM is given to you to find the relative atomic mass.

I hope this helps

Isotopes have a relative mass (of course) - they cannot have a relative isotopic mass per isotope, that just makes no sense.

Each individual isotope has a RIM
The element has a RAM based on the natural abundances of the isotopes.

Reply 4

Kvothe the Arcane

20

Original post by charco

Isotopes have a relative mass (of course) - they cannot have a relative isotopic mass per isotope, that just makes no sense.

Each individual isotope has a RIM
The element has a RAM based on the natural abundances of the isotopes.

I don't disagree with you.

Reply 5

Usman19999

2

What year r u guys in?

Posted from TSR Mobile

Original post by Kvothe the arcane

I don't disagree with you.

I know - I only answered because you asked for confirmation ...

Reply 7

Someoneanyone

OP

1

Original post by charco

Isotopes have a relative mass (of course) - they cannot have a relative isotopic mass per isotope, that just makes no sense.

Each individual isotope has a RIM
The element has a RAM based on the natural abundances of the isotopes.

I'm kinda confused again on the part where you say isotopes can't have a RIM per isotopes but each individual isotope has a RIM. what do you mean?

Original post by Someoneanyone

I'm kinda confused again on the part where you say isotopes can't have a RIM per isotopes but each individual isotope has a RIM. what do you mean?

An isotope is a particle. It has a specific mass. This can be expressed as a relative mass, but the same isotope ALWAYS has the same mass. There can be no such thing as an 'average' isotope mass.

Reply 9

Someoneanyone

OP

1

Original post by charco

An isotope is a particle. It has a specific mass. This can be expressed as a relative mass, but the same isotope ALWAYS has the same mass. There can be no such thing as an 'average' isotope mass.