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Question Date: 2005-10-08
Answer 1:

The Periodic Table of elements can tell you a lot about the elements. Oxygen with the symbol O has the atomic number 8 which means it is the 8th element in the table. The number eight also means that oxygen has eight protons in the nucleus.

The number of protons and the number of electrons are always the same in an element that is neutral and has no charge. Therefore oxygen has 8 electrons.

The number of neutrons normally varies and can be calculated from the atomic weight. If you click on the symbol in the periodic table at this web site


You will find that the atomic weight of oxygen is about 16. Since the weight of the protons and neutrons is about 1 (the electrons weigh almost nothing compared to protons and neutrons) and we know we have 8 protons in the nucleus, we can calculate the number of neutrons by subtracting 8 from 16 (16 - 8) which equals 8. The oxygen atom has therefore 8 neutrons, 8 protons and 8 electrons.

The number of valence electrons is equal with the group number. Since oxygen is in group 6 it means that it has 6 valence electrons.

Check out the periodic table from the web site above. You will see that the number of protons and electrons are easy to determine. (The number in the upper right corner) The number of neutrons are a bit trickier since most of the elements have isotopes.

Answer 2:

Oxygen is the 8th element in the periodic table. This means that Oxygen has 8 protons and 8 electrons. In order to get the number of neutrons you take the atomic weight in this case 15.9999~16 and you subtract it by the number of protons (16-8). To get the number of valence electrons just look at the numbers above the oxygen on the periodic table. Oxygen is in the 6A group which means that oxygen has 6 valence electrons.

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