1. Parts of an Atom
indiana.edu
Ms. Mandel
Honors Physical Science

2. The Structure of Atoms

3. Learning Target
I can differentiate between the parts of an atom.

4. What is an atom?
The smallest unit of an element.
The building blocks of all matter.

5. How small is an atom?
An atom is so small that a penny contains about 2 x 1022 or 20,000,000,000,000,000,000,000 atoms!!!

6. What are the parts of the atom?
Protons
Neutrons
Electrons

7. Parts of an Atom
The protons and neutrons make up the center or nucleus.

8. Small, dense (packed tightly) Contains protons and neutrons
The Nucleus
The center of an atom
Small, dense (packed tightly)
Contains protons and neutrons
most of the atom’s mass

9. Protons Located in the nucleus Positive charge (+)
Mass of 1 atomic mass unit (amu)
protons = positive

10. Have no charge - neutral Mass of 1 amu
Neutrons
Located in the nucleus
Have no charge - neutral
Mass of 1 amu
neutrons = neutral

11. Electrons Found outside of the nucleus in electron clouds
(think of rings around a target)
Negatively charged (-)
Mass of almost zero
Number of electrons equals the numbers of protons to cancel out the charges
(think of -1+1=0)
electrons = negative

12. What holds an atom together?
Electric force
Positive protons are attracted to negative electrons
The force holds the atom together

13. Learning Target Checkpoint
Parts
Charge
Location
Mass
Proton
Neutron
Electron
1 amu
Positive (+)
Nucleus
No charge
Nucleus
1 amu
Electron Cloud
Negative (-)
Almost zero

14. How many protons does C have?
Atomic Number
Atomic Number (Z) = # protons (p+)
Each element has a UNIQUE # of protons
How many protons does C have? 6

15. Mass Number
Mass Number (A) = number of protons (p+) + number of neutrons (n°) What is the mass number of Nitrogen if it has 7 neutrons? 14 # neutrons = A - Z

16. ? What is Z? 3 How many neutrons? 4 How many electrons?
May also be written:
Element name – mass number
Ex. Lithium - 7
chemteam.info
ieshermanosbilingual.blogspot.com
What is Z? 3
How many neutrons? 4
How many electrons? ?
chemteam.info

17. What element or elements is it?
Mass Number = 1
Mass Number = 2
Mass Number = 3
eqseis.geosc.psu.edu
What are these called?
Isotopes