Welcome...

Hello and welcome to another #steemitschool blog! Today's lesson will be on Isotopes and I hope you find the upcoming blog useful. Let's get started...

What is an Isotope?

Isotopes are different types of the same element. Isotopes have the same amount of protons/electrons but have a different amount of neutrons. 

In addition, Isotopes are also different to its original element in that it has different mass numbers. However, the atomic number is the same. 

Here is an example of a pair of isotopes - Carbon 12 and Carbon 13 

Carbon 12

number of:

protons = 6

neutrons = 6

electrons = 6

Carbon 13

number of:

protons = 6

neutrons = 7 

electrons = 6

Important note: the number of protons is always equal to the number of electrons in an atom. If they are not the same, the atom becomes an ion.

Since a lot of elements have isotopes, the relative atomic mass is used in replace of the mass number when mentioning the element as a whole. 

Here is a quick video to just reinforce what has been stated above. 

(Source: Youtube / fuse school)

What is the 'relative atomic mass?' 

Relative atomic mass = The average value (mass) of the isotopes for the element. 

How do you work out the relative atomic mass of an element?

Relative atomic mass = sum of (isotope abundance x isotope mass number)  ÷  sum of abundances for all isotopes.

Here is a working example...

Copper has 2 Isotopes, which are both stable. Calculate the relative atomic mass of copper to 1 decimal base.  Cu-63  abundance = 69.2 %      Cu-65 abundance = 30.8% 

working out...

Relative atomic mass =

 (69.2 x 63) + (30.8 x 65)  ÷ (69.2 + 30.2)

 = (4359.6 + 2002) ÷ 100 

= 6361.6 ÷ 100  

= 63.616 

= 63.6

Thanks for reading. I hope you learnt something new today and enjoyed this blog.

Information contained within this blog has been obtained from a GCSE AQA chemistry text book. 

Hope everyone's having a great weekend.

Jonathan ;)