Understanding Relative Atomic Mass

What is the relative atomic mass of an atom compared to?

• 1/16 of the mass of carbon-12

• 1/10 of the mass of carbon-12

• 1/12 of the mass of carbon-12

• 1/14 of the mass of carbon-12

Why do we use an average mass for elements?

• Because elements have different chemical properties

• Because elements have different numbers of protons

• Because elements have isotopes with different masses

• Because elements have different numbers of electrons

Why is the relative atomic mass of chlorine not exactly 36?

• Because it is a weighted average based on isotope abundance

• Because it is a simple average of its isotopes

• Because it is calculated using only chlorine-35

• Because it is calculated using only chlorine-37

What percentage of chlorine-35 is present in nature?

• 60%

• 75%

• 90%

• 50%

Why was carbon-12 chosen as the standard for relative atomic mass?

• Because it is the heaviest element

• Because it bonds with many elements and is common

• Because it is the lightest element

• Because it is the rarest element