Vocabulary Box
1. Proton: Positively charged subatomic particle located in nucleus
with a mass of 1 AMU
2. Neutron: Neutral subatomic particle located in nucleus. Has no
charge and a mass of 1 AMU
3. Electron: Negatively charged subatomic particle located in the
electron cloud with no mass.
4. Nucleus: Center of the atom. Contains nearly all the mass of
atom. Very dense and contains protons and neutrons.
5. Atomic Mass: total mass of atom = # of protons plus # of
neutrons
6. Atomic Mass Unit (AMU): same as one proton or one neutron
Atomic Structure
DO FIRST:
1. What is the Particulate Nature of Atoms?
August 19, 2014
2. Draw a diagram of a gas below.
Gases have the highest ______________ energy, temperature and
________________ among the 3 states of matter.
NEW MATERIAL: Atomic Structure
Matter is made of atoms, which are tiny particles that are the building
blocks of everything in the universe. The most current understanding
scientists have is that atoms look like this:
Most of the mass of an atom is
located in its center. The
center is called a nucleus. The
nucleus is very dense and very
small. The atom also has an
outer layer, called the
“electron cloud.” This region
has very little mass yet it takes
up much more space than the
nucleus. It is not dense at all.
We now know that atoms contain even tinier particles called subatomic
particles called protons, neutrons, and electrons. Protons & neutrons are
found in the nucleus. Electrons are found circling around in the electron
cloud. Two of the three particles have electrical charges. Protons are
positively-charged (+), while electrons are negatively-charged (-). The third
particle, the neutron, has no charge (0 or we say its “neutral”).
1. What are the 2 main areas of the atom?
2. What are the 3 particles that are found inside the atom? Write their
charges (+, 0, -) next to each in parentheses.
Atomic Structure
August 19, 2014
1. Which part of diagram represents the entire nucleus of the atom?
A.
B.
C.
D.
E.
Fill out the Table below by placing an X in the correct cell:
Subatomic
Particle
Proton
Electrical Charge
Positive
Negative
Neutral
Location
Inside
Outside
nucleus? nucleus
Mass
2. Which part of the diagram represents the
neutrons in an atom?
A.
B.
C.
D.
E.
X
3. Which part of the diagram represents the
particle with the least mass?
A.
B.
C.
D.
E.
Neutron
Electron
4. Which part of the diagram represents the protons? A. B. C. D. E.
5. Which part of the diagram represents a negatively charged particle? ____
Try on your own:
Where is most of the mass of the atom found?
Answer the questions below about atoms and subatomic particles:
1. What is an atom?
_________________________________________________________
2. What are the two main regions of an atom?
_________________________________________________________
3. Which subatomic particles are found in the nucleus?
_________________________________________________________
4. Which subatomic particles fly around in clouds?
_________________________________________________________
5. Which subatomic particle has no electrical charge?
_________________________________________________________
6. Which subatomic particle has a positive charge?
_________________________________________________________
7. Which subatomic particle has a negative charge?
__________________________________________________________
8. Which part of the atom has the most mass: the nucleus or the cloud?
__________________________________________________________
9. Which is the only particle not found in the nucleus?
__________________________________________________________
10. Which has more mass: 2 electrons, 1 electron and 1 proton, or 2
protons? __________________________________________________
What part of the atom contains most of the atom’s volume (takes up most
space)?
Which two subatomic particles contain opposite charges?
Which part of the atom is the densest (most dense)?
How do the masses of the three subatomic particles compare to one
another?
Subatomic
particle
Electrical
charge
Proton
Location in
the atom
Mass
1 amu
None
1
Very tiny (about
1836
amu)
Atomic Structure
August 19, 2014