2. Atoms & Elements
Atomic Mass
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So here for this example question, it says, which of the following represents an element from the first column with the greatest atomic mass? Alright. So our first column, if we look at this periodic table, our first column is this with all of these different elements. And remember, the number in red, which is not a whole number normally, that represents the atomic mass of any of these given elements. Now here, if we take a look, we have barium, ba. Again, later we'll learn about how the names are attached to the element symbol. Ba is not in the 1st column, here it's in the 2nd column. So this cannot be a choice. Then we're gonna say next that we have al. Al stands for aluminum. Aluminum is over here in the 3rd column, well all the way over here in this 13th column actually, so this is out. Next we have CS, this is cesium. Here it is right here. It's in the first column. It's pretty low down there. It's 132.91 for its atomic mass. Remember, that could be in grams per mole, atomic mass units, or daltons. So far, it looks like it's the highest one. The only one higher than that would be fr. Notice that in the bottom rows here, most of them are whole numbers. These are super large mass elements that are pretty unstable. They typically don't have numerous isotopes. As a result, they have no decimal places. So, next, so so far C looks like it's our best choice. If we look at D, we have LI, which is up here, not higher in mass, not greater in atomic mass, and then we have NA, which is right here. So it looks like C is our best choice. It has the greatest mass, atomic mass, from column 1 from the choices provided. So just remember we have our element symbols, we have our atomic masses, which normally are not whole numbers, and then we actually have whole numbers. Those represent our atomic numbers.
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