Average atomic mass learning check (5)

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 atomic mass of this element?

• 74.92 amu

• 24.97 amu

• 75.01 amu

• 74.51 amu

Calcium has three different isotopes. One has a mass of 35.00 amu; another has a mass of 41.00 amu; and another has a mass of 40.00 amu. Which isotope is the most abundant of the three?

• 40.00 amu
• 41.00 amu
• 35.00 amu
• impossible to tell

Atom X has 4 isotopes. 4.35% has a mass of 39.946 amu, 83.79% has a mass of 41.941 amu, 9.50% has a mass of 42.941 amu, and 2.36% has 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

Calculate the average atomic mass of silver.

• 106.38649amu
• 111.91896amu
• 107.8677amu
• 121

Tags

NGSS.HS-PS1-7

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

Atom 1 has Mass=12 Protons = 6

Atom 2 has Mass= 14 Atomic number = 6

Are these atoms isotopes of each other or different elements?

• Different; Elements - Mg & Si

• Different; Elements - Ar & Ca

• same; Isotopes of Carbon

• same; Isotopes of Magnesium