Boron Has Primarily Two Isotopes, One with an Atomic Mass

question 62

Multiple Choice

Boron has primarily two isotopes, one with an atomic mass of 11.0 amu and another with an atomic mass of 10.0 amu. If the abundance of the boron atom with a mass of 11.0 amu is 18.9 percent and the abundance of the other isotope is 81.1 percent, what would be the average mass of the boron atom?

• A)10.2 amu
• B)11.0 amu
• C)10.0 amu
• D)10.8 amu
• E)not enough information given

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Definitions:

Aromatic Ring

A stable ring-shaped molecule made up of alternating single and double bonds, common in many organic compounds.

O,p-director

Substituents that direct incoming substituents to the ortho and para positions in an aromatic ring during electrophilic substitution reactions.

Major Organic Product

The predominant compound produced through an organic reaction, usually of greatest interest or utility.

Cyano Substituent

A cyano substituent refers to a group containing a carbon triple-bonded to a nitrogen atom (-C≡N) attached to a molecular framework.