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All 7 questions. After you submit, each question shows the right answer and why. Back to the quick check
Water is not an element: it is a compound made of hydrogen and oxygen.
What decides which element an atom is?
Carbon-12 and carbon-14 are isotopes. What is different about their atoms?
Which of these is the correct symbol for the element sodium?
Boron is about 20% boron-10 (mass 10.0129) and 80% boron-11 (mass 11.0093). Calculate boron's average atomic mass to two decimal places.
CIAAW gives chlorine's standard atomic weight as an interval rather than a single number because the ratio of its isotopes varies between materials.
Explain the difference between an isotope's atomic mass and an element's standard atomic weight, using carbon as an example.
