Download Calculating the number of Protons, Neutrons, and Electrons.

Calculating the number of Protons,
Neutrons, and Electrons.
Using the atomic number and the
mass number of an element square.
The Atom
• Is about…..
– Anything that has matter/mass or takes up space.
– Made up of three subatomic particles (protons,
neutrons, and electrons)
Atomic Number
• Number of protons
• Used to determine what kind of
element/atom you have.
• Always a whole number
• Also, tells us the number of electrons in a
neutral atom.
Mass Number
•
•
•
•
Equal to the number of protons + neutrons
Equals the mass of the nucleus
Decimal number
Round to a whole number to use
Atomic Mass
• Average mass of all the isotopes for a certain
atom.
• Same as the mass number (for this year)
• Mass can change because we can add or
remove neutrons.
• Use the mass – atomic number to solve for
neutrons.
Element Square Key
8
O
Oxygen
15.999
Atomic Number
Symbol
Name of Element
Atomic Mass
Mass Number
Atomic Weight
Atomic Number = Protons and Electron
Calculate Neutrons = Rounded Atomic Mass – Atomic Number
EXAMPLE: 15.999 rounds to 16 so
 16 – 8 = 8
 Oxygen has 8 neutrons!
#1
Symbol
B
Atomic
Number
Protons
Neutrons
Electrons
Atomic
Mass
#2
Symbol
Atomic
Number
11
Protons
Neutrons
Electrons
Atomic
Mass
#3
Symbol
Atomic
Number
Protons
31
Neutrons
Electrons
Atomic
Mass
#4
Symbol
Atomic
Number
Protons
31
Neutrons
Electrons
37
Hint = Isotope
Think about what number will be different
Atomic
Mass
#5
Symbol
Atomic
Number
Protons
89
Neutrons
Electrons
Atomic
Mass
#6
Symbol
Atomic
Number
Protons
Neutrons
Electrons
Atomic
Mass
207
More Practice
• Complete the chart
• When complete you may color code the atoms
on the back