Science review
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Transcript of Science review
Science Review for Alana
What’s an atom?
Smallest unit of matter
Structure of an atom
Electron Cloud
Nucleus
Subatomic ParticlesIn the Nucleus:
Protons: + charge
Neutrons: no charge
Mass of each:1 atomic mass unit (amu)
In the Electron Cloud:
Electrons: - charge
Practically no mass
Neutral atom
Check
What are the two overall structures in the atom?
What are the names of the atomic particles?
What’s an element?
Atoms with different numbers of protons
Atomic Number
# of protons=atomic number Identification (student id# or SSN)
Why is it called “periodic”?
Check
Where are the protons located?
Where are the electrons located?
Where are the neutrons located?
Neutral atom
Mass Number
Protons + Neutrons
Exercise
Draw a neutral lithium atom (protons, neutrons, electrons) with an mass number of 7
Isotope
Atom with same # of protons but different # of neutrons (different mass number)
Radioactivity
Too many or too few neutrons compared to protons
UNSTABLE
It wants to be sane (more stable)…so it gets rid of something! Emits a particle or energy
Ever heard of uranium?
Types of nucleus radiation that can be emitted: Alpha Beta Gamma
Check
What is the atomic number?
Atomic mass
Weighted atomic mass of the isotope of an element
Structure of an atom
Electron Cloud
Nucleus
Electron cloud
Electrons arranged in Energy level
1st level can hold 2 electrons
2nd energy level can hold 8
3rd…18
4th…32
Outermost electrons called valence electrons – chemical bonds
Electron cloud
Exercise
Draw a neutral carbon atom with an atomic mass of 12
Draw the electron cloud of Na
Draw the electron cloud of Cl
Bonding
As it turns out, atoms bond together for a very simple reason: atoms like to have full valence shells
http://web.jjay.cuny.edu/~acarpi/NSC/5-bonds.htm
http://www.kentchemistry.com/links/bonding/bondingflashes/bond_types.swf
Ions
Atoms that are Not neutral
# Electrons not equal to # protons
Previous example of sodium and chlorine
Part K on review sheet
States/Changes of matter
Solids, liquids, gases
http://www.chem.purdue.edu/gchelp/liquids/character.html
http://www.clickandlearn.org/Gr9_Sci/Particle_Theory.htm
Solutions
http://www.chem4kids.com/files/matter_solution.html