Chemistry pt. 2: Isotopes

iMost of the mass in an atom comes from the amount of Protons and Neutrons in its nucleus. 

While every element is determined by the amount of Protons in its atom, the element Xenon is 54, and Copper is 29, but Neutrons are important too, not all atoms with different numbers of Neutrons are named "Isotopes". 

The sum of Neutrons and Protons in an atom is its "Mass number". For example: 
A is its Mass number, C is the Chemical Symbol and Z is the Atomic number:

                                                          A
                                                            C
                                                          Z

Let's take the element Silver or (Ag), you would need to add the amount of Protons and Neutrons together (47 Protons, 61 Neutrons) add them together you would get:

                                                         108 (total Protons and Neutrons)
                                                                Ag (chemical symbol)
                                                          47 (atomic number

Notice how we are filling in the numbers above like A, C and Z letters from the above diagram.

Another way to depict it is:

                                                            C-13 (carbon 13)

Which is carbon (C) and 13 is the atomic number, so for another one:

                                                            Au-78 (gold)

See the correlation, the element and then a hyphen or - symbol, then its atomic number.

But it is not all that easy, as atoms that have the same element can have different numbers of Neutrons, and these are dubbed as "Isotopes" which is the topic of today's post, as Isotopes have different numbers of Neutrons, they also have different mass numbers.

Ill just reuse this:

                                                          108 (total Protons and Neutrons)
                                                                Ag (chemical symbol)
                                                          47 (atomic number

Now, if you're told to figure out how many Neutrons does this element have, first just take the total mass (108) and minus 47 (the atomic number). which will give you the result of 61 Neutrons, or "108 - 47 = 61".

Now let's do it a little differently:

                                                         Pt-195

Now, you have to do it differently, so "Pt" is the element platinum, and platinum has 78 Protons, so all you have to do (again), is take the mass number in this case is 195, and minus it by 78 which it's amount of Protons, and "195 - 78 = 117", or 117 Neutrons.