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