Atomic Structure:
• Location: Where it is on the atom
• Charge: Electric charge (positive, negative or neutral)
• Mass: how big or small it is
Parts of the Atom:NUCLEUS
• The small center part of the atom that contains the neutrons and protons
• from Greek “karyon”, meaning kernel • Protons and neutron are
packed very tightly! • The density is the same
as having the entire mass of the sun squeezed into Chicago!
Parts of the Atom:ELECTRON CLOUD
• The large region around the nucleus that contain the traveling electrons
• 100,000 times larger in diameter than the nucleus!
• Impossible to determine the exact location of an electron within the cloud.
Parts of the Atom:PROTON
• Location: the center of the atom
PROTON
From Greek “Protos” meaning first
From suffix “ion” meaning subatomic particle
• Charge: positive
• Mass: About 1 a.m.u, almost 2000 times larger than the electron, slightly smaller than the neutron
Parts of the Atom:NEUTRON
• Location: the center of the atom
NEUTRON
From the noun “neutral”
From suffix “ion” meaning subatomic particle
• Charge: neutral
• Mass: about 1 a.m.u., almost 2000 times larger than the electron, slightly larger than the proton
Parts of the Atom:ELECTRON
• Location: the outer part of the atom, surrounding the nucleus
ELECTRON
From the word “electric”
From suffix “ion” meaning subatomic particle
• Charge: negative
• Mass: almost 0 a.m.u., almost 2000 times smaller than the proton and neutron.
Comparing Locations:Electrons are on the outside of the
atom. They spin around the nucleus in an electron cloud.
The protons and neutrons are packed tightly together in the center of the atom.
The space between the electron cloud and nucleus is huge!
If the nucleus was the size of a golf ball, the electron cloud would be 1.5 miles away!
Comparing Charges:
Electrons have a negative charge, protons have a positive charge and neutrons have no charge.
Comparing Mass:
Electron (so tiny, you can’t see it)
If a proton was the size of the blue sphere on the left, then the electron would be one pixel of the screen—so small, that you can’t see it! Click here to see website showing this.
Protons and Nuetrons are almost 2000 times larger than electrons
Getting Smaller….We now know that matter is made up of even smaller matter:
Particles in various combinations
Quarks Leptons
up
down
charm
strange
top
bottom
electron muon tau
electron neutrino
muon neutrino
tau neutrino
Up and Down Quarks3 quarks (up + up + down) make up a proton 3 quarks (down + down + up) make up a neutron
proton neutron
electron
Bohr Model of a HELIUM ATOM
+N
N
+-
-
proton
electron neutron
Shell
Question: What are some limitations of this model?
Answer: Electrons are too large and not in an electron cloud, electrons are too close to the nucleus.
ATOMIC STRUCTURE
Particle
proton
neutron
electron
Charge
+ ve charge
-ve charge
No charge
1
1
nil
Mass
nucleus
nucleus
shell
Location
ATOMIC STRUCTURE
Electrons are arranged in Energy Levels or
Shells around the nucleus of an atom.
• first shell a maximum of 2 electrons
• second shell a maximum of 8
electrons
• third shell a maximum of
8 electrons
3rd shellCan hold up to 8 electrons
Adapted from http://www.sciencespot.net/Media/atomsfam.pdf
2nd shellCan hold up to 8 electrons
1st shellCan hold up to 2 electrons
NucleusContains protons and neutrons
Analyzing Elements on the Periodic Table
the number of protons in an atom
the number of protons and neutrons in an atom
Be4
9.012 Atomic Mass
Atomic number
* Number of electrons = number of protons
Beryllium
1, 2 or 3 letters. First letter always capitalized, second always lower case.
Element Symbol
* Number of neutrons = Atomic Mass (rounded to nearest) – Atomic Number
Element Name
Created by G.Baker www.thesciencequeen.net
So let’s try it….How to draw a Lithium atom
First, look at the Periodic Table
Second, determine the number of protons (Look at the atomic number)
Then determine the number of neutrons (Atomic mass – atomic number)
Then determine the number of electrons
(Look at the atomic number)
3
Li
Lithium7
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