Atomic Numbers

Atomic Number, Average Atomic Mass, Mass Number, Isotopes

Multiple Choice

How is average atomic mass determined?

• By adding all of the protons and neutrons together.

• by summing the masses of the element's isotopes, each multiplied by its natural abundance on Earth

• By multiplying of often protons and neutrons occur and adding up the averages.

Multiple Choice

What are AMU's

• Atomic Mass University

• Atomic Mass Units

• Atoms mean unity

• All Mass United

Multiple Choice

What are AMU's

• The unit used to measure the mass of atoms and molecules. Equal to 1/12 the mass of Carbon-12

• Unit to measure the radius of an atom

• Equal to a gram

• The unit used to measure large quantities of atoms

Multiple Choice

What does the atomic number represent?

• The number of electrons

• The number of protons

• The number of neutrons

• The number of protons and neutrons together.

Isotope Symbols

As you can see to the right there are certain ways elements and isotopes are represented as symbols. There is the element symbol (the biggest part). Then the upper number will the the mass number (number of protons + number of neutrons) and the lower number is just the atomic number (number of protons).

Isotope Symbol Examples

As you can see here the element is Cu (copper), and it has a mass number of 63 and atomic number of 29. With this information I can determine that this copper atom has 34 neutrons.

 $63-29=34$  

Multiple Choice

What does the mass number represent?

• The number of electrons

• The number of protons

• The number of neutrons

• The number of protons and neutrons together.

Multiple Choice

What does the atomic number represent?

• The number of electrons

• The number of protons

• The number of neutrons

• The number of protons and neutrons together.

Multiple Choice

If an atom has 5 protons and 6 neutrons what is the proper name of the isotope?

• Boron-1

• Boron-11

• Carbon-11

• Carbon 11

• Boron Carbonate

Multiple Choice

How many neutrons does an atom of symbol pictured have?

• 26

• -26

• 70

Multiple Choice

How many protons does an atom of symbol pictured have?

• 22

• 26

• 70

Multiple Choice

What is the total number of particles in the nucleus atom of symbol pictured have?

• 22

• 70

• 48