00:03
Hey there, in this question we want to write our complete symbol and we're told that we have an oxygen atom.
00:10
So looking at the periodic table we see that oxygen's symbol is o.
00:15
But when we're writing the complete symbol we also have to include the atomic number as a subscript before the symbol and the mass number as a superscript before the symbol.
00:28
Okay, so we know we have oxygen and looking at the periodic table we can get the atomic number.
00:34
For oxygen it is 8.
00:37
The atomic number is just the whole number that we find in each box of the periodic table.
00:42
Alright, but then we need the mass number.
00:45
And mass number is defined as the number of protons plus the number of neutrons.
00:56
Well we're told the number of neutrons but what we need is the number of protons.
01:02
Well, there's another definition we're missing here...