Question

Which of the following isotopes is used as a standard for atomic mass units (Daltons)?

A) Hydrogen-1
B) Lithium-7
C) Carbon-12
D) Nitrogen-14
E) Oxygen-16

Please select the correct isotope that serves as the standard for atomic mass units.

Answer 1

Carbon-12, ¹²C, is the isotope used as a standard for atomic mass units, with one atom of carbon-12 having a mass of 12 amu.

Step-by-step explanation:

The correct isotope used as a standard for atomic mass units, also known as Daltons, is Carbon-12, ¹²C. By definition, one atom of carbon-12 is assigned a mass of 12 atomic mass units (amu), with an atomic mass unit being defined as a mass equal to one twelfth the mass of an atom of carbon-12. This standard provides a baseline by which all other isotopic masses are compared. It is important to remember that Carbon-12 contains six protons and six neutrons, totaling a mass number of 12, and in its neutral form, it will also have six electrons.