Unit 2 test

What is the atomic number?

• the number of protons in the nucleus

• the number of protons and neutrons in the nucleus

• the number of neutrons in the nucleus

• the number of protons in the energy levels

What is the atomic number of this atom?

• 1

• 3

• 4

• 7

What is the mass number of this atom?

• 1

• 3

• 4

• 7

Most of the mass in an atom is made up of _____________________?

• protons and electrons
• protons and neutrons
• neutrons and electrons
• electrons and quarks

How is the number of neutrons in the nucleus of an atom calculated?

• Add the number of e- and p+ together
• Subtract the number of e- from p+
• Subtract the number of p+ from the mass number
• Add the mass number to the number of e-

What subatomic particles would you find in the nucleus of an atom?

• Protons only
• Protons and Neutrons
• Neutrons and Electrons
• Protons and Electrons 

Which subatomic particles contribute the most to the mass of an atom?

• Protons, Neutrons, Electrons
• Protons only
• Protons and Electrons
• Protons and Neutrons

An atom has 10 protons, 15 neutrons and 10 electrons what is its mass number.

• 20

• 10

• 35

• 25

How many electrons does this atom have?

• 2

• 4

• 6

• 10

An atom has an atomic number of 15 and a mass number of 31. How many protons are there in the atom?

• 15
• 31
• 16
• 47