<p>So, does the periodic table report mass of an element, or rather, the average mass (atomic weight?) of an element as I read it was not possible to report the mass number of an element, just the average.</p>
<p>The periodic table reports the weighted average of empirical measurements of the element.</p>
<p>Atomic Mass=Weighted average of all isotopes of an element=the number with decimal places on the periodic table</p>
<p>Mass Number=Number of protons+neutrons=Rounded atomic mass</p>
<p>So basically, what those two answers mean is, that it’s not possible to report just a general mass and you can only report the atomic weight (the average mass) correct?</p>
<p>Pretty much. There are several isotopes of the same element, so there isn’t a general mass.</p>
<p>Off-topic: Do we need to know about spectra? Because I’m a little hazy on that subject.</p>
<p>Or orbitals/quantum numbers?</p>
<p>^ that’s for AP Chem. Don’t overkill; I’ve never seen those topics on my real exam. Neither my friend did.</p>
<p>So, spectra/orbitals/quantum numbers, mostly out. Ok. Thanks!</p>
<p>False. I took the SAT Chemistry twice (for practice) and I have seen a set of questions on:</p>
<ol>
<li>Spectra</li>
<li>Quantum Numbers and Orbitals</li>
</ol>
<p>However the Quantum Numbers and Orbitals are easy. Just learn how to count by them: 1s2 2s2 2p6 etc. and use common sense. They also love asking questions on the shape of s, p, and d orbitals.</p>
<p>^How specifically do they ask about the shape?</p>
<p>Is it enough to know that s = spherical, p=dumbell, and d has 5 orientations?</p>
<p>^ Yes .</p>
<p>is there a term for the shape of the p orbital? (other than "5 orientations)</p>
<p>Also, what do we need to know about spectra? All I know is that when electrons absorb energy, they move from the ground state to an excited shape and that it is released on photons. Do we need to know about Lyman, Balmer, and Paschen series?</p>
<p>bumpers…</p>