What are all of those numbers and letters on the elements?
Those numbers and letters represent multiple properties of that element. They can represent the average number of sub-atomic particles for that element or the number of sub-atomic particles of a specific atom. But for this article, we will be discussing the symbols found on the periodic table.
What's that small number on the top-left corner?
That's the atomic number. The atomic number is the number of protons in an atom's nucleus. For example, iron has 26 protons in its nucleus. Meaning its atomic number is 26. If it didn't have 26 protons, it would be a different element.
What's are those bolded letters?
That is the atomic symbol of that element. Those are shortened names of those element. They represent the elements in chemical formulas to help one figure out which element are in each compound.
For example, a CO2 molecule consists of a carbon atom, and 2 oxygen atoms.
Although, capitalization is important. For CO2, which is 1 carbon atoms and 2 oxygen atoms, is different from Co2, which is 2 cobalt atoms.
What are those numbers below the element's name?
That is the average atomic mass of that element. Atomic weight composed of the mass of the protons and neutrons of an element. Average atomic mass is composed of the average weight of all known isotopes of that element.
I feel there are some inaccuracies in this article, or maybe it just needs to be phrased differently. In the first paragraph, we talk atoms and elements as though they were different things in the periodic table. Well, yes, they are different things, but as far as they are used in the periodic table, they are practically the same.
ReplyDeleteThe second paragraphs is correct. I would just add that the number of protons is exactly what makes an element what it is. Twenty-six protons make iron. If you add a proton or subtract a proton, it would automatically be a different element.
In the third paragraph: you will never find CO2 in the periodic table. You will find the element C and you will find the element O. But the periodic table does not list compounds, which is what CO2 is. Nor will the periodic table list Co2, but it will list down Co.
And finally, in the fourth paragraph, the atomic mass is, very simply, the number of protons plus the number of neutrons in an atom. Often these are equal, so C, which has 12 protons, would also have 12 neutrons, and therefore, an atomic mass of 24. But of course, carbon has isotopes, so it can have 13 neutrons, in which case, it would have an atomic mass of 25.
Now if we are going to talk about averages, then we are talking about atomic WEIGHT, which is the AVERAGE number of protons and neutrons of an element, taking in consideration ALL its known isotopes.
In other words, a single element may have multiple atomic masses, but only one atomic weight.
https://www.khanacademy.org/science/chemistry/atomic-structure-and-properties/modal/v/atomic-weight-and-atomic-mass
ReplyDelete