Answered

The table below gives the atomic mass and relative abundance values for the three isotopes of element [tex]$M$[/tex].
\begin{tabular}{|l|l|}
\hline Relative abundance (\%) & Atomic mass (amu) \\
\hline 78.99 & 23.9850 \\
\hline 10.00 & 24.9858 \\
\hline 11.01 & 25.9826 \\
\hline
\end{tabular}

What is the average atomic mass (in [tex]$amu$[/tex]) of element [tex]$M$[/tex]?

A. 2.86
B. 5.36
C. 24.30
D. 24.98



Answer :

GinnyAnswer
To determine the average atomic mass of element \( M \), we will use the weighted average formula, which considers both the relative abundance and the atomic mass of each isotope. Here are the steps involved:

1. List the given data:
- Isotope 1: Relative abundance = \( 78.99\% \), Atomic mass = \( 23.9850 \) amu
- Isotope 2: Relative abundance = \( 10.00\% \), Atomic mass = \( 24.9858 \) amu
- Isotope 3: Relative abundance = \( 11.01\% \), Atomic mass = \( 25.9826 \) amu

2. Calculate the weighted contribution of each isotope:
- Isotope 1 contribution = \( 0.7899 \times 23.9850 \)
- Isotope 2 contribution = \( 0.1000 \times 24.9858 \)
- Isotope 3 contribution = \( 0.1101 \times 25.9826 \)

3. Sum the contributions to get the total weighted atomic mass:
- Total weighted atomic mass = \( (0.7899 \times 23.9850) + (0.1000 \times 24.9858) + (0.1101 \times 25.9826) \)

4. Divide the total weighted atomic mass by \( 100 \) to find the average atomic mass:
- Average atomic mass = \(\frac{ (0.7899 \times 23.9850) + (0.1000 \times 24.9858) + (0.1101 \times 25.9826) }{100}\)

Performing these calculations, we find that the average atomic mass of element \( M \) is approximately:

\( 24.30 \)

Thus, the correct choice from the given options is:

24.30

Other Questions