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Hello, welcome to problem number 20.
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In problem number 20, we have a chart to complete.
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It's going to be chart b.
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And these are all neutral atoms.
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So since they're neutral atoms, they do not have a charge.
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So let's go ahead and get started.
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In the first one, we are told that we have cobalt and we are given a number of neutrons as being 32.
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So the first thing we need to fill in is the atomic number.
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So the atomic number can be found on the periodic table.
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Looking up cobalt, we see that cobalt's atomic number is 27.
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So the atomic number is 27.
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The next thing we need is the mass number.
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Mass number is defined.
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Let me just put this over here.
00:58
Mass number is the number of protons plus the number of neutrons.
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So we know we have an atomic number of 27.
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So that means 27 protons.
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And we're given 32 neutrons.
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So 27 plus 32 gives us a mass number of 59.
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So that means we can now write out the isotope by writing the symbol, which is coo for cobalt, big c, little o.
01:36
Make sure your first letter is capitalized.
01:39
Second one's lowercase.
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And then the mass number goes as a superscript before.
01:45
And the atomic number can be written as a subscript before.
01:50
So this would be our isotope.
01:54
That means we have 27 protons.
01:58
This is a neutral atom, so it must have the same number of electrons.
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And we already know that it has 32 neutrons.
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So that would be our series of answers for the cobalt.
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Okay, let's look at the next line...