Page 8 - Pro test
P. 8
Mass Number
As you can see in the diagrams of the atoms in the table
above, the largest part is the centre where the protons
and neutrons are situated. This is called the Nucleus and
it contains most of the mass of the atom.
This is why the Mass Number is the combined total of
the protons and neutrons.
“ Always round off the Mass Number. Hydrogen’s mass
number of 1.00794 will be rounded to 1.
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