4.2 Structure of Atoms

-Quick Lab: Investigating Charged Objects (12/16/15) 10pts

Learning Objective - I can explain that like charges repel and unlike charges attract.
Observations (explain what you see happening)
1. 
2. 
3. 
4.
5.

What we know about magnets...

A magnet is any material or object that produces a magnetic field. This magnetic field is responsible for the property of a magnet: a force that pulls on other ferromagnetic materials and attracts or repels other magnets. A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. Materials that can be magnetized, which are strongly attracted to a magnet, are called ferromagnetic. Although ferromagnetic materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field.

Some facts about magnets include:

• the north pole of the magnet points to the geomagnetic north pole (a south magnetic pole) located in Canada above the Arctic Circle.
• north poles repel north poles
• south poles repel south poles
• north poles attract south poles
• south poles attract north poles
• the force of attraction or repulsion varies inversely with the distance squared
• the strength of a magnet varies at different locations on the magnet
• magnets are strongest at their poles
• magnets strongly attract steel, iron, nickel, cobalt, gadolinium
• magnets slightly attract liquid oxygen and other materials
• magnets slightly repel water, carbon and boron

The mechanics of how do magnets work really breaks right down to the atomic level. When current flows in a wire a magnetic field is created around the wire. Current is simply a bunch of moving electrons, and moving electrons make a magnetic field. This is how electromagnets are made to work.

-4.2 The Structure of an Atom (right side)
Learning Objective: I can identify the structure of an atom and the atomic number and mass number of elements

Notes:
-Every living and nonliving thing is made up of matter, and all matter is made up of atoms - the smallest unit of matter that cannot be broken down by chemical means.

-Atoms are made of:
protons +
electrons -
neutrons (no charge)

-Since each atom has the same number of protons and electrons, they have no overall charge (cancels out charge)


-The Periodic Table contains elements, a substance made up of atoms that have the same number of protons. An element's identity is based on its atomic number, which is the number of protons in one atom of that element. 


For example, carbon's atomic number is 6.

-The chemical reactions covered in this chapter involve electrons.

-A change in the number of electrons does not change an atom's identity.

-Atomic structure:
Electrons fill the outer shells of an atom
Only 2 electrons can fill the innermost shell
Outer shells hold eight and prefer to have their outer shell filled, making them stable.
-Hydrogen is stable when it only has 2 valence electrons

-A compound is a substance make of the bonded atoms of two or more different elements.

Watch this video 'Atomic Structure' to help explain the structure of atoms

Make vocabulary flashcards:

proton

neutron

electron 

atomic number

mass number

isotopes

-Do 4.2 worksheet: Atomic Structure

Watch NOVA Video: Island of Stability (start at 3:38; 13:10)
1. What is element #92, the last of the naturally occurring elements?
2.What makes a nucleus 'doubly magic?'
3. How do you 'add' atoms together?