Personally the first thing i do, is expand the number
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4 sig figs.
An oxygen atom is always made up of 8 protons.
The mass number of an atom is made up of both protons and neutrons.
So to find out the number of neutrons, you subtract the number of protons from the mass number.
Number of neutrons = Mass number - number of protons
So for oxygen with a mass number of 18:
There are: 18 - 8 = 10 neutrons
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Answer:
There are 10 neutrons in an atom of oxygen with a mass number of 18.
(option C)
I think the correct answer would be the last option. The ocean zone which has the lowest water pressure would be the uppermost zone which is the Epipelagic zone. This zone is also called as the euphotic zone or the sunlit zone. It is the region which receives the most sunlight in order to allow photosynthesis.
