Chem I: Atomic Mass Review

Compute the average atomic mass for this element.

• 27.977
• 28.09
• 28.976
• 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.
How many protons does this element have?

• 32
• 33
• 34
• no way to know

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

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

Which subatomic particles make up the mass of an atom?

• protons only

• protons and neutrons

• protons, neutrons and electrons

• protons and electrons

Tags

NGSS.MS-PS1-1

How many neutrons are there for an atom with a mass of 20 and 11 protons?

• 9

• 11

• 20

• 31

All of the following are found in the nucleus EXCEPT

• Proton

• Neutron

• Electron

• There are no exceptions. All are found in the nucleus

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-8

Boron has two existing isotopes, boron-10 and boron-11. Which of the two isotopes is the most abundant? Why?

• Boron-10 since its mass is the closest to the average mass reported in the periodic table

• Boron-11 since its mass is the closest to the average mass reported in the periodic table

• Boron-10 since this isotope contains an equal amount of protons and neutrons

• Boron-11 since this isotope is the heaviest of the two

What is the name of the atom pictured here?

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

One of the isotopes of sulfur is represented as sulfur-35 or S-35. What does the number 35 signify?

• number of protons

• number of neutrons

• atomic number

• mass number