객관식
Which of the following is an isotope of lithium?
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4. Atoms and Elements
Isotopes
객관식
How many neutrons are in a atom?
A
6
B
0
C
4
D
2
검증된 단계별 안내1
Identify the isotope notation given: \(\mathrm{He}^{4}\). The superscript 4 represents the mass number (A), which is the total number of protons and neutrons in the nucleus.
Recall that the atomic number (Z) of helium (He) is 2, which means it has 2 protons.
Use the relationship between mass number, protons, and neutrons: \(A = Z + N\), where \(N\) is the number of neutrons.
Rearrange the formula to solve for neutrons: \(N = A - Z\).
Substitute the known values: \(N = 4 - 2\), which gives the number of neutrons in the helium-4 atom.
