chapters 1 & 2 atoms and elements and chemical reactions (period 5) chemistry … ·...
TRANSCRIPT
CHEMISTRY REVIEW
Chapters 1 & 2
Atoms and Elements and Chemical Reactions (Period 5)
T = CHAPTER 1 ATOMS AND ELEMENTS
Elements and Atoms
Matter - anything that takes up and has mass
Elements – A substance that cannot be broken down
into any other substance
Compound – a substance made of two or more
elements that is combined chemically in a specific
ratio.
Mixture – when two or more substances are
combined-non chemically (dirt, air, mulch, fish in
water, mud)
Atom – the smallest particle of an element
T = CHAPTER 1 ATOMS AND ELEMENTS
Atomic Theories
Daltons - composed that atoms can not divided, they are all alike, every compound is made of atoms in specific ratios, atoms can not be created or destroyed.
Thomson – chocolate chip cookie model (electrons are everywhere)
Rutherford - Gold foil experiment (the existence of a nucleus)
Bohr – onion – orbitals (looks like the planets orbiting the sun which would be the nucleus and planets are the electrons in the orbits
Cloud – electrons can be anywhere
Modern (Chadwick) - neutrons
Elements and Periodic Table Period –horizontal
Group (family) – column- vertical
Metals – most of the chart until Group 13
Non Metals – Groups 14-18
Semi Metals – Staircase 13-17
Atomic Number – number in the box= # protons if neutral = # of electrons
Symbols – the shortened version of an element ex. Oxygen = O, Lithium = Li, Sodium = Na, Sulfur = S
Valence Electron – Electrons on on the outer orbital. They have the highest energy level. Gr. 1 and 2 like to give up electrons because losing 1 or 2 electrons is the easiest way to be KING(noble gases). Halogens like to take electrons to gain noble status.
T = CHAPTER 1 ATOMS AND ELEMENTS
T = CHAPTER 1 ATOMS AND ELEMENTS
Elements and Periodic Table Metals - luster, malleable, ductile, conducts heat,
conductive, sea of electrons
Semi Metals – can exist as both a metal or a non metal depending on temperature, what it is paired with!
Non Metals - all non metals have at least four valence electrons and Halogens become stable when they gain or share electrons
Electron Dot Structure – shows the number of valence electron as dots around the symbol
Atomic Orbital Structure - p/n in middle, layer like an onion or planets, circles. First orbit has 2, all others filled up to 8. The outermost circle holds the valence electrons
T = CHAPTER 1 ATOMS AND ELEMENTS
Group Names Alkali Metals – Group 1
Alkaline and Earth – Group 2
Halogens – Group 17
Nobel Gases – Group 18
Covalent Bonding – Share electrons
Usually Form between non metals
Become more stable when they share
Non Polar – Electrons shared equally
Polar – Electrons shared unequally
Single Bonds – 2 electrons
Double Bonds 4 electrons
Triple Bonds 6 electrons
Do not conduct electricity
T = CHAPTER 1 ATOMS AND ELEMENTS Ionic Bonding
Transfer of electrons
Always polar
Bond is due to the attraction of the opposite charges
Form crystals
High melting points
Conduct electricity
Metallic Bonding – Attraction between a positive metal ion and the electrons
surrounding it
Consists of a positively charged metal ion embedded in a sea of electrons
Alloy – material made of two or more elements that have the characteristics of a metal
Every metal ion is held by a metallic bond
Conduct Heat and Electricity
Lust and Malleability and ductility
CHAPTER 2 OBSERVING CHEMICAL REACTIONS
T= Observing Chemical Change
Properties and Changes of Matter
Physical Properties –
Observable change without changing the substance
Ex squishing, vaporization, Change of state,
Chemical Properties
Observable change which DOES change the substance into another substance
Ex. Fire(burning), oxidized, rusted, tarnish
Physical Change
A change in its state but the substance is not changed
Chemical Change
Changing the substance into another substance
T= OBSERVING CHEMICAL CHANGE
Evidence for Chemical Reactions
Sensing a change in smell
See a precipitate
Solid formed from two liquids
Change of heat/temperature
Exothermic – release of heat (feels hot)
Endothermic – absorbing heat (feels cold)
Change of color
T= DESCRIBING CHEMICAL CHANGE
Chemical Equation Reactant + reactant YIELDS Product + Product
Short easy way to show a chemical reaction using symbols
Yield = arrow
Product is the end solution/material/substrate
Reactants are the substances in the beginning
Coefficient is the number in front which represents the number of molecules of that particular substance
Conservation of Mass The principal stating that matter is not created nor
destroyed during a chemical reaction Closed System – Where substances can not come in or be let out!
Balloon, air bag(partial), class jar with lid, zip lock bag, sealed box,
Open System – System in which matter can enter and or escape Beaker (open), campfire, cooking pot
T= DESCRIBING CHEMICAL CHANGE
Balancing Chemical Equations
Both sides have the same number of each type of
atom.
Write the equation
Count the atoms (on each side)
Use coefficients to balance the atoms
Look Back and Check
T= CLASSIFYING CHEMICAL REACTIONS
Replacement - Switch Partners
Synthesis – Simple to Complex
Decomposition - Complex to
Simple
T= CONTROLLING CHEMICAL REACTIONS
Temperature
Surface Area – Simple to Complex
Concentration - Complex to Simple
Inhibitor - Slows down a reaction
Catalyst – Speeds up a reaction
T= CONTROLLING CHEMICAL REACTIONS
Temperature - adds or removes energy – increased temp increases the reaction rate.
Surface Area – greater surface area increases the reaction
Concentration – higher concentration usually increases the reaction rate
Inhibitor - Slows down a reaction
Catalyst – Speeds up a reaction
T= FIRE AND FIRE SAFETY
Temperature - adds or removes energy – increased temp increases the reaction rate.
Surface Area – greater surface area increases the reaction
Concentration – higher concentration usually increases the reaction rate
Inhibitor - Slows down a reaction
Catalyst – Speeds up a reaction