So # of protons is always going to just be the atomic number, which if you look on a periodic table, its the big one in the corner. So you can look that up easy for Li, Ca, and Se.
The numbers tell you the atomic mass over the atomic number.
Since the two particles that give an atom mass (neutrons and protons) both have a mass of about 1 amu, the atomic mass is essentially # of neutrons + number of protons.
So # of neutrons = atomic mass - number of protons.
The number of electrons is the same as the number of protons unless the atom is actually an ion.
If so, then if you had something like Li, it would have 3 electrons (same as # of protons). But if you had Li+, it would only have two. The plus shows that you lost one negative charge (one electron), hence why you have 2. <span />
The answer would be: Igneous Rocks
Answer:

Explanation:
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In this case, for the separation of the benzene-toluene mixture, we can use the following mole balances including the given mole fraction at each stream per species:

That can be solved by using a solver for P1 (benzene-rich flow) and P2 (toluene-rich flow):

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Elements can be chemically combined into compounds, therefore, a compound consists of two or more elements combined, in definite proportions, by chemical means. Compounds may be formed by combining atoms of their constituent elements by ionic bonds or by covalent bonds.
Nonferrous alloys do not contain iron as the name suggests. Ferrous is the latin word for iron. These alloys use precious metals such as gold, silver, platinum and other metals like copper, aluminum, lead, zinc and even alloys like brass. Answer is D.