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Metal, Nonmetal or Metalloid?All elements can be separated into these 3 major categoriesHow do we put all objects into these main groups?
MetalsShinyCan conduct heat and electricity
They can be formed into sheets and wire
Examples: tin, gold, copper
NonmetalsDull (non-shiny)POOR conductors of heat and electricity
Solids are brittle (break easily)
Examples: iodine, sulfur, neon
What do water, baking soda, sugar and salt all have in common?Even though many of these substances have
different properties, they are all made of certain elements.
These elements CHEMICALLY combine to form new substances
Example: hydrogen + oxygen = water Sodium + Chlorine = SaltThese new substances are called compounds
What is a compound?A compound is a pure substance composed of TWO or more elements that are CHEMICALLY combined.
A particle of a compound is called a molecule
Fill out the following table, use page 60 in your textbook
Compound Elements Combined
Table Salt Sodium + Chlorine
Water Hydrogen + Oxygen
Vinegar Hydrogen + Carbon + Oxygen
Carbon Dioxide Carbon + Oxygen
Baking Soda Sodium + Hydrogen + Carbon + Oxygen
Properties of CompoundsMost of the time a compound has very different
properties compared to the elements that make that compound.
Salt is a really good example of this…
Breaking Down CompoundsBreaking down compounds can be difficult.Two ways to break down a compound:
Apply heat Apply and electric current
In Industry In Nature
Where do we find compounds?
Aluminum is created by breaking down aluminum oxide (AL + O)
Ammonia (N + H) is used in fertilizers
Nitrogen compound such as proteins are needed for all living things
Carbon Dioxide (C+O) is a crucial part of photosynthesis and respiration
How do compounds form?
Take a look at this water molecule. It has ONE oxygen atom and TWO Hydrogen atoms. Water ALWAYS looks that way no matter what, but why? Why not just one hydrogen atom, why not three?
It’s all about the electrons!Atoms love to give, take
and share electrons. When two or more elements do that, a compound is formed.
The number of electrons is usually equal to the number of protons.
Electron ShellsElectrons like to hang out in groups
TWO electrons always hang out by the nucleus
Every other shell is a group of EIGHT electrons
Atoms want to feel COMPLETE… That’s why atoms give each other electrons, or
share the ones they have.
What is a mixture?A mixture is combination of substances that are PHYSICALLY combined
When substances are mixed they DO NOT create a new substance
Not All Mixtures Look The Same Sometimes you can see the
different parts of the mixture (like a salad)
But other times it is hard to see the different parts
A SOLUTION is a mixture where you cannot easily see the different parts of a mixture
Like This ------------------------
Solutes and SolventsSolutions are made of two parts SOLUTES or SOLVENTS
Solvents DO THE DISSOLVING like the water in saltwater
Solutes ARE THE ONES DISSOLVED like the salt in saltwater
Think about the Kool-Aid, which parts are the solutes, which are the solvents?
Solutes = Sugar and powderSolvents = Water
Look on page 67, complete the following chart…
States Examples
Gas in Gas Dry air (oxygen in nitrogen)
Gas in Liquid Soft Drink (carbon dioxide in water)
Liquid in Liquid Antifreeze (alcohol in water)
Solid in Liquid Salt Water (salt in water)
Solid in Solid Brass (zinc in copper)
ConcentrationConcentration is the amount of a substance in a solutionWhich of these graduated cylinders has the highest concentration?
Solubility Solubility is the ability for a substance to dissolve in another.
Some substances dissolve really easily, other do not.
Homework
1) Create a T-Chart comparing compounds and mixtures. Have at least 5 ideas on each side.
2) Give three examples of solutions, for each solution, name the solute and the solvent
3) What is solubility? Name one substance that has a high solubility and one substance that has a low solubility.