average atomic mass

24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
How many protons does this element have?

• 32
• 33
• 34
• no way to know

An isotope has three forms.  30% have a mass of 4 amu, 20% have a mass of 5 amu and 50% have a mass of 3 amu.  Average atomic mass will be closest to

• 2 amu
• 3 amu
• 4 amu
• 5 amu

Calculate the average atomic mass of silver.

• 106.38649amu
• 111.91896amu
• 107.8677amu
• 121

Atom 1 has Mass=12  Protons=6
Atom 2 has Mass= 14 Electrons=6
Are these atoms isotopes of each other or different elements?

• Different Elements - Mg & Si
• Different Elements - Ar & Ca
• Isotopes of Carbon
• Isotopes of Magnesium

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

What is the name of the atom pictured here?

• Nitrogen
• Nitrogen-15
• Nitrogen-7
• Nitrogen-8

Which of the following could have 82 neutrons?

• W-182
• Ta-181
• Cs-132
• Ba-138

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?

• 9.012, Beryllium
• 12.011, Carbon
• 6.941, Lithium
• 10.812, Boron