Chemistry

• Physical Property 


  Describes an element on its own
• Chemical Property 


  How it reacts with other chemicals
• Evidence that would indicate a chemical change has occurred

  -New gas or new solid

  -Colour Change

  -Heat Change

  -Suspension of solution

  -Dissolving

  -Bubbling/ Fizzing
• Billard Ball Model 


  -John Dalton

  -Atoms are solid, invisible and indivisible
• Plum Pudding Model 


  -JJ Thompson

  -Negative particles are embedded in a positive sphere
• Planetary Model 


  -Ernest Rutherford

  -proved there was a nucleus

  -Electrons orbit nucleus where ever
• Bohr Diagrams 


  -Neils Bohr

  -Electrons have specific energy levels

  -Electrons can move between energy levels by absorbing or releasing energy
• Quantum Mechanics 


  -uses mathematics to predict the behaviour of electrons

  -Cloud of charges
• Cations 


  -When something loses electrons to become positive

  -Metals tend to lose electrons
• Anions 


  -When something gains electrons to become negative

  -Non-Metals tend to gain electrons
• Octet Rule 


  Molecules are most stable when the outer shell is full
• Valence electrons 


  Electrons in the outer shell
• Molecular Compounds 


  -Consists of 2 or more Non-Metal atoms bonded together

  -These atoms are combined by sharing electrons

  -This type of bond is called a single covalent bond
• Physical Properties of Molecular Compounds

  -Solid, liquid, or gas at room temperature

  -Do not conduct electricity when dissolved in water

  -Many do not dissolve in water
• Ionic Compounds 


  -A metal and a non-metal combine to form an ionic compound

  -Ions are attracted to each other since they have opposite charges

  -Electrons are passed from one atom to another

  -Cations and Anions are held together by single covalent bonds
• Properties of Ionic Compounds

  -All Ionic Compounds are solid at room temperature. Ionic solids are hard and brittle

  -All can be dissolved in water (Aqueos state)

  -Form a coloured or colourless solution

  -Are good conductors when dissolved in water
• Acid Properties 


  -Solutions conduct electricity

  -React with metals to produce hydrogen gas

  -Taste Sour

  -Neutralizes bases

  -Turns blue litmas paper red

  -PH is below 7
• How to recognize acids by its formula

  -All acids contain H and are aqueous

  -The H in the formula is at the beginning of the formula or at the end as a part of a -COOH group
• Properties of Bases


  -They can be identified by the hydroxide ion, OH-

  -Bitter tasting

  -Slippery to touch

  -PH is above 7

  -Turn red litmus paper blue

  -Neutralized by acids
• How to Identify Bases by their formula

  -Most bases have OH in their formula

  -Only exception to that is NH3, ammonia
• Evidence of Chemical Change

  -Temperature

  -Light

  -Sound

  -Electricity

  -Odour change

  -Colour Change

  -Formation of a gas
• Exothermic


  Reactions that release energy
• Endothermic


  reactions that absorbs energy
• Conservation of matter


  Matter cannot be created nor destroyed
• Precipitate 


  When a new solid is made between two solutions that are mixed together
• Hydrocarbon Combustion Reactions 


  -Hydrocarbons are compounds that contain carbon and hydrogen and sometimes oxygen
• Where is most of the mass of an atom located

  Nucleus
• What takes up the most volume

  Electrons
• The atomic number equals the number of what subatomic particles?

  Protons and electrons