C HAPTER F OUHREE A “Mixture” of Chapters 3 and 4

T HE “S TUFF ” OF S CIENCE Matter: Anything that has mass and volume What is matter? What isn’t matter?

T EENY W EENIE, I TZY B ITZY Matter is made out of elements An element is a substance that cannot be broken down into simpler substances by chemical ways These elements are composed of similar atoms An atom is the smallest part of an element that still contains properties of an element.

W HAT MAKES UP AN A TOM ? Any atom is made up of 3 parts: Electron : A particle that has a negative charge The particles circle around the center of the atom. Neutron : Does not contain a charge Located in the center which is the nucleus Proton : A particle that has a positive charge Located in the center with the neutron

S OLIDS Tightly packed Vibrate (jiggle) but generally they don’t move Has a fixed volume and shape (Rigid) Not easily compressible (little free space) Does not flow easily

L IQUIDS Particles close together They vibrate, move about, and slide past each other. Takes the shape of the container that it is in Compressible Flows easily

G ASES Well separated particles with no arrangement Gas vibrates and moves freely with high speeds Assumes shape and volume of container Compressible Flows easily

P LASMA A lot of similar characteristics to gases How they are different from gases Made up of a free electron Do not find them too often in nature

T HE T ABLE THAT HAS IT ALL Periodic Table : Contains all the elements that we know of, both natural and man-made. There are 90 natural elements and 119 in total The 29 other elements are man-made element and are known as synthetic elements.

H OW TO R EAD A P ERIODIC T ABLE The columns are called groups Notable Groups: Halogens, Noble Gases Noble Gases : The most stable elements because they naturally do not bond with anything. Halogens : “Salt-former”, they make salt The rows are called periods

W HAT DO ALL THOSE NUMBERS M EAN ? Atomic Number: Tells the number of protons in the nucleus Atomic Mass: How heavy the actual element is. Atomic Mass

O NE M ORE T YPE OF N UMBER Mass Number: The number of protons and neutrons in the nucleus But wait this isn’t on our tables! How do we ever figure this out? We round the atomic weight. This gives us the mass number We can also figure out how many neutrons this way too!

I SOTOPES Isotopes : Atoms of the same element that have different number of neutrons How do we know its an Isotope? It has a number at the end of the name that is not its atomic mass

I F E LECTRONS A RE NOT IN THE N UCLEUS, W HERE ARE THEY ? Electrons exact location is not known. We normally call the area in where they happen the Electron Cloud. However, we do know they have different energy levels, we call each level an Orbital. 1 st Orbital: 2 electrons 2 nd Orbital: 8 electrons 3 rd Orbital: 18 electrons 4 th Orbital: 32 electrons

A TOM /E LEMENT P ROJECT

T HE T ABLE IS S PLIT INTO 3 CATEGORIES 1. Metals Shiny or metallic luster (its coating/polish) Good conductor of heat and electricity All metals but one are solid at Room Temp. (Hg) They are malleable (hammered) and ductile (wire) Most of the elements on the table are metal

S ECOND AND T HIRD C ATEGORY 2. Non-metals Dull look Poor conductors Many are gases, if solid they are very brittle Located mostly on the right side of the table 3. Metalloids Has characteristics of Metals and non-metals Some shiny Many are good conductors but not as good as metals All metalloids are solids

W HY DO WE NEED THIS TABLE ? It is one way that we can communicate between all countries and with every scientist across the world. It helps us save space when writing them out because we have developed a symbol for each one.

C OMBINING E LEMENTS Compounds : Two or more elements that have come together to form something different Compounds are going to be different from the elements that make them up. Law of definite proportions : A given compound will always be made of the exact same number of atoms of the elements that make it up. Another word for compounds is Molecules

H OW TO W RITE A C OMPOUND /M OLECULE Requires a Chemical formula : Its composed of elemental symbols and numbers that tell how many atoms of each element is in the substance.

P URE S UBSTANCES AND M IXTURES Pure Substance : Matter that has the same composition and properties throughout. Mixtures : Two or more substances that come together but don’t combine to make a new substance.

T WO T YPES OF M IXTURES Homogeneous Mixture : Uniform throughout Cannot tell one part from the next Ex: most Juices, Soft Drinks, Milk, Brass, Stainless Steel Heterogeneous Mixture : Not Uniform throughout Made out of noticeably different parts Usually separated or separate over time Ex: Mixed nuts, juices with pulp, blood, salsa

P HYSICAL P ROPERTIES Physical Properties : Characteristics you can see that does not change the actual make up of the material. Mainly focuses on appearance (size, color, shape) Ex: Flexible, Ductile, Malleable, Hardness,

C HEMICAL P ROPERTIES Chemical Properties : Characteristic of a substance that allows it to change into a new substance. Ex: Reactivity or Flammability

P HYSICAL C HANGES Physical Change : Any change in the size, shape, or form of an object. It doesn’t actually change what the object is. One example of physical changes is that changes that occur between the stages of matter…

M OVEMENT BETWEEN STAGES OF MATTER

C HEMICAL C HANGES Chemical change : one material changed into another substance A chemical change usually causes 1 of the 4 things to happen 1. Produce light or heat 2. Form a precipitate (solid) 3. Produce a gas 4. Change in color