Average Atomic Mass

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 12.0, Carbon
• 12.011, Carbon
• 10.81, Boron
• 10.812, Boron

Calculate the atomic mass of an element if 60.4% of the atoms have a mass of 68.9257 amu and the rest have a mass of 70.9249 amu.

• 70.0 amu
• 70. amu
• 69.7 amu
• 69.72 amu

Nitrogen has three occurring isotopes: Nitrogen-13, Nitrogen-14, Nitrogen-15. Which isotope is the most abundant?

• Nitrogen-13
• Nitrogen-14
• Nitrogen-15
• Based on the information given, it cannot be determined

Calculate the average atomic mass of silver.

• 112 amu
• 111.9 amu
• 107.9 amu
• 108 amu

What is the atomic mass of Neon?

• 10
• 20.18
• 10.18
• 20.18