Multiple Choice
Which of the following is closest to the atomic mass of sodium (Na)?
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2. Atoms & Elements
Atomic Mass
Multiple Choice
Which element is used as the standard for defining the atomic mass unit (amu)?
A
Hydrogen
B
Carbon
C
Carbon-12
D
Oxygen
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Verified step by step guidance1
Understand that the atomic mass unit (amu) is a standard unit used to express atomic and molecular weights.
Recall that the amu is defined based on a specific isotope of an element to provide a consistent reference.
Identify that the element used as the standard is Carbon, specifically the isotope Carbon-12.
Know that one atomic mass unit is defined as exactly \( \frac{1}{12} \) of the mass of a Carbon-12 atom.
Therefore, Carbon-12 serves as the reference point for all atomic mass measurements in chemistry.
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