Question

The table below shows the atomic mass and natural abundance of the two naturally occurring isotopes of lithium. Which numerical setup can be used to determine the atomic mass of naturally occurring lithium?

Answer 1

The numerical setup that can be used to determine the atomic mass of naturally occurring lithium is:

• (0.075)(6.02u) + (0.925)(7.02u) [option 1]

How to determine the numerical set up?

To obtain the numerical set up to determine the atomic mass of naturally occurring lithium, first, we shall list out the given parameters. This is shown:

• Mass of Li-6 = 6.02
• Abundance of Li-6 = 7.5%
• Mass of Li-7 = 7.02
• Abundance of Li-7 = 92.5%
• Numerical set for the atomic mass of lithium =?

`Average\ atomic\ mass = (Mass\ of\ isotope\ *\ abundance)/(100) \\\\`

Thus, the numerical set will be:

`= (6.02u\ *\ 7.5)/(100)\ +\ (7.02u\ *\ 92.5)/(100)\\\\= (6.02u\ *\ 0.075)\ +\ (7.02u\ *\ 0.925)\\\\= (0.075)(6.02u)\ +\ (0.925)(7.02u)`

Thus, the correct answer is option 1

Complete question:

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