CRCT STUDY GUIDE

Atoms and Molecules Atoms Smallest thing that can be identified as material Only consists of one element Smallest particle that retains its chemical properties ATOMS ARE THE Building BLOCKS OF MOLECULES Molecules Are made of atoms and are much bigger Consists of more than one atom (element) Held together by chemical bonds

Pure Substances ELEMENTSCOMPOUNDSMIXTURES Consists of only one atom Can NOT be broken down in to simpler types of matter by chemical OR physical means Molecules consists of 2 or more atoms chemically bound together Can be 2 or more different elements Has properties different than component element, but always contains the ratio of its component atoms Consists of 2 or more elements or compounds physically intermingled Can be separated!

Pure Substances and Mixtures Web MATTER Pure SubstancesMixtures ELEMENTS Pure substances One type of particle Identified by properties Mg, Na, Cl COMPOUNDS Pure substances that consists of 2 or more elements MgO, NaCl, HOMOGENEOUS The same! Uniformly distributed Blood, Air, Water HETEROGENOUS Different! Not uniformly distributed Rocks, Oil and water, Soup, Pizza

SOLIDSLIQUIDSGASESPLASMA has a definite shape and volume Particles are very close together and vibrate in place Heating a solid will cause it to become a liquid Example Has a definite volume, but takes the shape of its container Particles move fast enough to overcome some of the attractions between them Particles slide past each other until the liquid takes the shape of its container Heating a liquid will cause it to become a gas Cooling a liquid will cause it to become a solid Example Has no definite shape or volume Particles move quickly—they can break away from one another Particles take the shape of the container--amount of empty space between particles can change When a gas is cooled it becomes a liquid Example Most common form of matter— but don’t see a lot of it on earth because it is too hot Water heated to 1500 degrees Fahrenheit would be a plasma Similar to a gas but has highly ionized that occurs at high temperatures does not have a definite shape or a definite volume unless enclosed in a container Examples: stars, neon signs, lightning

Solid Particles are tightly compact Particles vibrate without the ability to move freely Definite shape and volume Solid Animation

Liquid Particles are tightly compact, but able to move around close to each other No definite shape, but definite volume Liquid Animation

Gas Particles can easily spread out or move close together Particle move freely and with a lot of energy No definite shape or volume Gas Simulation

Plasma Exist at extremely high temperatures (several million degrees Celsius) Particles are broken apart Particles move freely and with extremely high energy This form is not too common on earth, however it is the most common form of matter in the universe No definite shape or volume? Examples: Florescent and neon lights, lightning, aurora borealisaurora borealis Why do you think this is the most common form/state of matter in the universe?

Properties of Matter Physical Property Any property of matter that can be observed or measured without changing the identity of the matter Examples color shape taste density state/phase D = M V

Properties of Matter Chemical Property Any property of matter that describes a substance based on its ability to change into a new substance Examples flammability reactivity with vinegar reactivity with oxygen Iron + Oxygen  Iron oxide (rust) 2Fe + 3O 2  Fe 2 O 3

Physical vs. Chemical Properties of Matter Physical (pages 44 and up)Chemical (pages 50 and up) DENSITY MELTING POINT BOILING POINT THERMAL CONDUCTIVITY SOLUBILITY DUCTILITY STATE MALLEABILITY SHAPE REACTIVITY COMBUSTIBILITY FLAMMABILITY BURNING

Comparing Physical and Chemical Properties Substance/MatterPhysical PropertyChemical Property HeliumLess dense than airNonflammable WoodGrainy textureFlammable Baking sodaWhite powderReacts with vinegar to produce bubbles Powdered sugarWhite powderDoes not react with vinegar Rubbing alcoholClear liquidFlammable Red food coloringRed colorReacts with bleach and loses color IronMalleableReacts with oxygen

Changes in Matter Physical Change DOES NOT CHANGE THE IDENTITY OF THE MATTER INVOVLED a change in shape, size, color, or state a change without a change in chemical composition a change that is reversible Examples tearing paper cutting your hair change in state

Changes in Matter Chemical Change a change in which a substance becomes another substance having different properties!!!! a change that is not reversible using ordinary physical means Changes that usually cause heat, sound, light, odor, fizzing/foaming, color changes You usually need more than one of the above characteristics to be considered a chemical change! Examples combining sulfuric acid and sugar burning a piece of wood soured milk

Periodic  Periodic Law  Periodic Table Something periodic occurs at regular or at least generally predictable intervals Periodic law - physical and chemical properties of the elements are periodic functions of their atomic numbers Periodic Table of Elements – a table of the elements, arranged by atomic number, that shows the patterns in their properties; based on the periodic law Can you think of anything that is periodic?

3 Classes of Elements ClassColor Metal Non-Metal Metalloid Using this as a guide, color code your periodic table to show the three classes. Start by highlighting the “zig-zag.”

Metals Location Found on the left of the zigzag line/staircase on the periodic table (exception  Hydrogen) Chemical Properties Have few electrons in their outer energy level, thus lose electrons easily Physical Properties ductile, good conductors, malleable, shiny, most are room temperature What metal is not a room temperature? Image taken from: lement-Photo-Gallery.--98/Sodium.htm 11 Na Au

Atoms with Few Electrons in their Outer Energy Level Notice: only 1 electron in outer level Notice: only 2 electrons in outer level Na Be 9.012

Non-Metals Location Most found to the right of the zigzag line/staircase on the periodic table Chemical Properties Most have almost full outer energy levels, thus they tend to gain electrons; some have completely full outer level Physical Properties not ductile or malleable, not shiny, poor conductors, most are solid, but some are gas at room temperature Image taken from: Image taken from: 16 S Cl

Atoms with Full or Almost Full Outer Energy Level Notice: 7 electrons in outer level – almost full Notice: 2 electrons in outer level – FULL Notice: 6 electrons in outer level – almost full F O He 4.003

The Periodic Table of Elements periods groups

Period (Row) Properties Seven periods on a periodic table (numbered from the top down) Atomic numbers and atomic masses increase as you move from the left to the right in a period All atoms of the elements in the same period have the same number of orbitals/levels All atoms of the elements in a specific period have that respective number of orbitals/levels – Example Period 1 = 1 orbital Period 2 = 2 orbitals Period 3 = 3 orbitals Etc…

PERIODIC TABLE Group (Family) Names Alkali Metals Alkaline Earth Metals Transition Metals Boron Group Carbon Group Nitrogen Group Oxygen Group Halogens Noble Gases

Group (Family) Properties Eighteen groups on the periodic table (numbered from left to right) Atomic numbers and atomic masses increase as you move from the top down in a group (family) Atoms of elements in the same group have the same number of electrons in the outer orbitals/levels of their atoms (known as valence electrons) – Exceptions: Transition elements (3-12) Hydrogen (could be 1 or 17) Helium (actually has 2 valence electrons) Elements in groups usually have similar physical and chemical properties

THE LAW OF CONSERVATION OF MATTER p.403 STATES: Matter can NOT be created nor destroyed in an isolated system. It can only be converted from one form to another. EXAMPLES: If I burn paper; the appearance of the matter changes, BUT matter is NOT lost. The weight of the ash and the gas produced weighs the same. ***We will discuss more LAWS of Conservation in our Energy Unit.

Practice Counting Atoms