객관식
A sample of chlorine contains two naturally occurring isotopes: chlorine-35 (mass = 34.969 u, abundance = 75.78%) and chlorine-37 (mass = 36.966 u, abundance = 24.22%). What is the average atomic mass of chlorine?
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2. Atoms & Elements
Isotopes
Multiple Choice
How many electrons are present in one atom of the isotope 13C?
A
6
B
13
C
7
D
12
검증된 단계별 안내1
Identify the element from the isotope notation. The isotope is given as \(^{13}\mathrm{C}\), where \(\mathrm{C}\) stands for carbon.
Recall that the atomic number (number of protons) of carbon is 6. This number is the same for all isotopes of carbon and determines the number of electrons in a neutral atom.
Understand that the superscript 13 in \(^{13}\mathrm{C}\) represents the mass number, which is the sum of protons and neutrons in the nucleus.
Since the atom is neutral, the number of electrons equals the number of protons. Therefore, the number of electrons in one atom of \(^{13}\mathrm{C}\) is equal to the atomic number of carbon, which is 6.
No further calculation is needed because the isotope notation does not change the number of electrons in a neutral atom.
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