A hypothetical element Q has two naturally occurring isotopes: Q-10 ( ) and Q-11 ( )

CHEMISTRY · Single correct · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties

Problem

A hypothetical element Q has two naturally occurring isotopes: Q-10 (

10.0\,\text{amu}

) and Q-11 (

11.0\,\text{amu}

). The reported average atomic mass of Q is

10.8\,\text{amu}

. Which statement is most consistent with these data? (a)

\text{Atoms of Q-10 and Q-11 are present in nearly equal numbers in a natural sample of Q.}

(b)

\text{Atoms of Q-11 are substantially more abundant than atoms of Q-10, making up roughly }80\%\text{ of all Q atoms.}

(c)

\text{Atoms of Q-10 are substantially more abundant than atoms of Q-11, making up roughly }80\%\text{ of all Q atoms.}

(d)

\text{Atoms of Q-10 contribute negligibly to the average atomic mass because their mass is lower than that of Q-11.}