Isotope Abundance

An isotope has three forms.  10% have a mass of 4 amu, 20% have a mass of 5 amu and 70% have a mass of 6 amu.  Based on the percentage of abundances above, the average atomic mass will be closest to...

• 3 amu

• 4 amu

• 5 amu

• 6 amu

• 7 amu

Element Z has 2 natural isotopes. One isotope has a mass of 15.0 amu and a relative abundance of 30%. The other isotope has a mass of 16.0 amu and a relative abundance of 70%. Estimate the average atomic mass for this one element.

• 15.0 amu

• 16.0 amu

• 15.7 amu

• 16.9 amu

Tags

NGSS.MS-PS1-1

If the abundance of ⁸⁵Rb is 72.2% and the abundance of ⁸⁷Rb is 27.8%,

What is the average atomic mass of rubidium?

Tags

NGSS.HS-PS1-7

Calculate the average atomic mass of silver.

An unknown element has three isotopes. Given the abundances and relative masses, determine which element it is.

HINT: You do NOT need to calculate anything here.

• Uranium

  Mass: 238.03

• Fluorine

  Mass: 19.00

• Mercury

  Mass: 200.59

• Polonium

  Mass: 209

Tags

NGSS.HS-PS1-8

1.00794 is the (a)   atomic ​ (b)   for hydrogen

• minimum
• number
• average
• maximum
• mass

Tags

NGSS.HS-PS1-1

The average relative atomic mass of Vitellium (Vi) must be ​ (a)   the mass of the isotope called ​ (b)  

• closest to
• Vi–193.
• Vi–191
• Vi–188
• equal to

Tags

NGSS.HS-PS1-8

Using the atomic masses and relative abundance of the isotopes of nitrogen given, determine the average atomic mass of nitrogen.

N-14: 14.003 amu; 99.63% N-15: 15.000 amu; 0.37%

• 14.003 amu

• 14.007 amu

• 14.506 amu

• 15.000 amu

• 14.002 amu

Tags

NGSS.HS-PS1-7

The 3 isotopes of Oxygen. are shown.

The average atomic mass of oxygen is 15.9994 amu.

Which isotope is most likely to have the greatest abundance in nature?

• O–16

• O–17

• O-18

• all three isotopes may be equally abundant

Tags

NGSS.MS-PS1-1

An unknown element has two naturally occurring isotopes. One has a mass of 10.01 and % abundance of 19.8%. The other has a mass of 10.99 and % abundance of 80.2%. Calculate the atomic mass.