Name

 

What is an atomic mass?

Lesson Review

Complete the following.

  1. The total mass of the protons and neutrons in an atom is called the____________________________ .
  2. One amu is equal to the mass of one _________________________________________ .

 

3. The element _____________________________________ has a mass number and an atomic number of 1.

 

4. The total number of __________________________ in an atom is determined by subtracting the atomic number from its mass number.

 

5. Neutrons and ___________________________________________________________ have the same mass.

 

6. The total number of protons and neutrons in the nucleus of an atom is called the __________________________________________________ .

 

7. The mass of an atom is measured in _________________________________________________________ .

8. Each ______________________________________________________________ has its own

mass number.

 

9. The element ________________________________ has an atomic number of 8 and a mass number of 16.

 

Skill Challenge

Skills: synthesizing, comparing

Use the table below to answer the following questions.

        Element

Atomic Number

  Mass Number

Helium

2

4

Sodium

11

23

Iron

26

56

Gold

79

197

Lead

82

207

 

1. How many neutrons are in an atom of helium?____________________________________

 

2. How many protons are in an atom of iron? ________________________________________

 

3. How many neutrons are in an atom of lead? ________________________________________

 

  1. How many electrons are in an atom of sodium? ______________________________________