<span>The light spectrum that results from the light produced by an excited electron moving from a higher energy level back down to a lower energy level is an emission spectrum. The emission spectrum is formed by the electromagnetic radiation released by the transition in energy state.</span>
In the equation,
2Al(s) + 3Cl2(g) —> 2AlCl3(s),
the large number "3" in front of Cl2 indicates the the number of moles of Chlorine molecules needed to balance the equation.
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