Quiz - 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 element is it?

• Beryllium

• Carbon

• Lithium

• Boron

Compute the average atomic mass for silicon:

• 28.11

• 28.09
• 28.086

• The average mass cannot be determined from provided information.

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.
What is the average mass of this element?

• 74.92 amu
• 24.97 amu
• 75.01 amu
• 74.51 amu

Magnesium exists as the three isotopes shown. What is the average atomic mass of magnesium?

• 20.74 amu

• 22.56 amu

• 24.32 amu

• 24.31 amu

An element with 4.35% have a mass of 49.9461 amu, 83.79% have amass of 51.9405 amu, 9.50% have a mass of 52.9407 amu, and 2.36% have a mass of 53.9389amu.

• 52.00 amu

• 52.19 amu
• 53.45 amu
• 17.33 amu

What does the 1.00794 stand for?

• Molar Mass in AMU's

• atomic number
• average atomic mass in amu"s

• does not mean anything

Tags

NGSS.HS-PS1-7

The average atomic mass of an element is the ___.

• average of the mass number and the atomic number for the element

• weighted average of the masses of the isotopes of the element

• total mass of the isotopes of the element

• total number of subatomic particles in the nucleus

Calculate the average atomic mass of the element iron (Fe) using the following data:

[Isotope / % abundance]

[Iron 54 / 6% ] [Iron 56 / 92% ] [ Iron 57 / 2% ]

• 53.70 amu

• 54.90 amu

• 5592.0 amu

• 55.90 amu