Section 2 – Matter and Atomic Structure Learning Target - 3a. Review – Use a model to classify matter based on its structure and properties. pure substance vs mixture element vs compound homogeneous vs heterogeneous atoms and molecules (DOK 1)

Section 2 – Matter and Atomic Structure Learning Target - Use Cornell notes as a way to process information in science class.

Today we are taking notes - Cornell Notes Why? This is a way of writing notes that will help you learn. We are going to learn this technique and use it on and off through the rest of the school year. Some of your other classes may already be using this technique.... ours is the ‘new style’.

Let’s Start Take a separate lined sheet of paper and fold your paper in thirds.

Next – Name Date Pd Notes on Matter EQ: How is MATTER classified? HEADING: (1)put your name, date, pd and title on the top of the paper. (2) Write down the essential question. This is the ‘big question that we are trying to answer with this set of notes. (3) Draw a line across the paper – just below your heading.

Next – Name Date Pd Notes on Matter EQ: How is MATTER classified? Use this 2/3rds of the paper for notes We will use this 1/3rd of the paper later.... leave it blank for now TAKING NOTES: You will use the space below the heading line for notes. Your notes will be written in the 2 columns on the right side of the paper. We will use the left hand column later in the process. You may want to draw a line separating the first column from the last two columns

Let’s Start - Remember – only write on the two right hand columns. Copy down the information from the slide – including headings Important points / key terms / Any added details from the discussion.

MATTER anything that has mass and takes up space ? What isn’t matter? energy

Properties of matter Physical properties: These properties can be observed or studied without changing the matter into something else. Examples: [write a few of these down] density, color, size, shape, melting point, boiling point, freezing point

Properties of matter Chemical properties Used to characterize materials in reactions that change their identity changes are often irreversible Examples: flammability, reactivity with other substances like water or acid

Changes to matter Physical changes do not produce a new substance. They may involve changes of state (gas / liquid / solid ) Think about a piece of wood, a piece of paper, or a piece of metal. What can we do to them that does not result in something new? wood – chop it butter – melt it metal – make it into a wire

Changes to matter A chemical change will produce a new substance. These changes require a chemical reaction. Think about a piece of wood, a piece of paper, or a piece of metal. What can we do to them that DOES result in something new? wood – burn it butter – brown it metal – react it with acid

Types of Matter There are many ways matter can be classified, but the simplest classification is based on the different types of matter. Pure substances vs. mixtures Elements vs compounds Homogeneous vs heterogeneous mixtures Do you recall these terms from middle school? Let’s see...

Substance A form of matter that has – constant composition (is the same throughout the universe) and – characteristic properties (has properties that help identify it) sometimes called a pure substance

Element A pure substance that cannot be broken down by chemical means. Each element is defined by its atomic number (the number of protons they posses). The smallest unit of an element is called an atom!

Element Examples: (write down a few of these ) Iron (Fe)Gold (Au)Silver (Ag) Mercury (Hg)Titanium (Ti)Aluminum (Al) Note: 7 elements are special... They are called diatomic elements... Can you tell why? hydrogen (H 2 ) nitrogen (N 2 ) oxygen (O 2 ) fluorine (F 2 ) chlorine (Cl 2 ) bromine (Br 2 ) iodine (I 2 ) The smallest unit of these special diatomic elements are called molecules.

Compound a substance formed when two or more DIFFERENT chemical elements are chemically bonded together Examples: (write down a few of these ) – H 2 O – dihydrogen monoxide – yep – it is water – NaCl – sodium chloride – table salt – C 6 H 12 O 6 – glucose – the sugar in your blood – C 12 H 22 O 11 – sucrose – table sugar – CaCl 2 – calcium chloride – the active ingredient in deicer for your driveway – CH 3 CH 2 OH – ethanol – the alcohol in alcoholic beverages

Compound The smallest unit of a compound is either a – molecule – when the compound is held together by covalent bonds – Formula unit – when the compound is held together by ionic bonds More about this later....

Mixtures A mixture is a physical combination of substances. does not have definite and constant composition. – For instance, coffee is a mixture, but it’s composition (make-up) is different from place to place A mixture can be separated by physical means. Two types of mixtures: – Homogeneous – Heterogeneous

Homogeneous mixtures has the same composition throughout – If you tested one part of the mixture it would be the same as a different part of the mixture Examples: [write a few of these down] – cup of coffee – beaker of salt water – glass of Kool-aid – balloon full of air – glass of grocery store milk – energy ‘shot’

Some Special Homogeneous mixtures Solutions - particles are so small they do not settle out and they do not scatter light Colloids – particles are small enough that they do not settle out, but they do scatter light

Heterogeneous mixtures does not have the same composition throughout Examples: [write a few down] muddy water a bucket of sand, salt, and nails Blood raw milk

Some Special Heterogeneous Mixtures Suspensions - particles are small – but big enough to scatter and even block light – and they do settle out

Demo – Solutions, Colloids, Suspensions Three large bottles, each filled with a mixture Bottle 1 – solution of copper(ll) nitrate (light blue) – particles are soooooooo small, a laser light passes through without being seen in the mixture Bottle 2 – water with 1-2 drops of milk or cream – particles are still small – too small to settle – but large enough to be seen and large enough to scatter laser light – so the laser light shows as it passes through this mixture. Bottle 3 – water with small scoop of clay... These particles are large enough to be seen – and large enough to settle out... And large enough to scatter the laser light.... Perhaps even block the laser light...