Percent Abundance of Isotopes

Isotopes of an element have a different number of...

• Protons

• Neutrons

• Electrons

• Mass

Rubidium has two common isotopes, ⁸⁵Rb and ⁸⁷Rb. If the abundance of ⁸⁵Rb is 72.2% and the abundance of ⁸⁷Rb is 27.8%, what is the average atomic mass of rubidium?

• 85.468 amu

• 37 amu

• 85.6 amu

• 86.4 amu

There are two primary isotopes found in any sample of copper: copper-63 and copper-65. The isotope ⁶⁵Cu composes 69.2% of the sample and ⁶³Cu comprises the other 30.8%. Based on this data, what is the atomic mass of copper?

• 29 amu

• 63.546 amu

• 64.4 amu

• 63.6 amu

Tags

NGSS.HS-PS1-7

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

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

4.35% of all X atoms have a mass of 39.946 amu. 83.79% have a mass of 41.941 amu, 9.50% have a mass of 42.941 amu, and 2.36% have a mass of 43.939 amu. What is the average atomic mass of atom X?

• 41.97 amu
• 42.19 amu
• 10.43 amu
• 40.04 amu

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

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