Multiple Choice
According to modern science, what was the approximate chemical composition of the solar nebula?
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2. Atoms & Elements
The Atom
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A neutral atom of aluminum-27 contains:
A
13 protons, 14 electrons, and 13 neutrons
B
14 protons, 14 electrons, and 13 neutrons
C
27 protons, 27 electrons, and 0 neutrons
D
13 protons, 13 electrons, and 14 neutrons
Verified step by step guidance1
Recall that a neutral atom has an equal number of protons and electrons. Since the atom is aluminum-27, identify the atomic number of aluminum, which is the number of protons.
The atomic number of aluminum is 13, so the atom must have 13 protons and, because it is neutral, also 13 electrons.
The mass number (given as 27) is the sum of protons and neutrons: \(\text{mass number} = \text{protons} + \text{neutrons}\).
Use the mass number and the number of protons to find the number of neutrons: \(\text{neutrons} = 27 - 13\).
Combine these results to confirm that the neutral aluminum-27 atom contains 13 protons, 13 electrons, and 14 neutrons.
