Role of Protons, Neutrons, and Electrons in an Atom

Determining the number

of Protons, Neutrons and Electrons

• Go through each slide and take notes in your notebook

Squares of the Periodic Table

• Atomic Number

– (# of protons)

• Symbol
• Name
• Atomic Mass

– (protons + neutrons)

Multiple Choice

What's the atomic number of Mercury?

• 6

• Hg

• 80

• 200.59

Multiple Choice

What's the Atomic Mass of Mercury rounded?

• 200

• 201

• 80

• 81

Atomic Number

• Number of protons is also the number of electrons

• Each element has

different atomic number

Multiple Choice

If Gallium has 31 protons how many electrons does Gallium have?

• 69

• 31

• 70

Calculating neutrons

• If protons + neutrons =

atomic mass

• Then atomic mass –

protons = neutrons

Calculating neutrons practice

• Atomic Mass=37
• Atomic Number =17
• # of Neutrons =

Atomic Mass=35
Atomic Number =17
# of Neutrons =

​M - A = N

Multiple Choice

Using your periodic table-- DFind the number of Neutrons for Barium.

• 81

• 137

• 56

• 82