Block 3

• How do scientists classify matter into categories?

  Pure Substances and mixtures
• What categories is Pure Substances classified in?

  Compounds & Elements
• What categories is mixtures classifies in?

  Heterogeneous & Homogeneous
• What are compounds?


  2 or more different elements combined.

  examples: H20, CO2
• What are elements?


  Only one kind of atom.

  Example: Oxygen, Nitrogen
• What are Solutions?


  Solutions are homogeneous mixtures and can be solid, liquid, or gas.
• What is the difference between the types of Mixtures & Solutions?

  The main difference is that solutions are always homogeneous while mixtures are mostly heterogeneous.

  A solution cannot be separated physically while the components of a mixture can be.
• How do scientists describe matter's observable & measurable qualities?

  Through physical properties & characteristics.

  These include things like mass, volume, density, & temperature.
• How do we calculate density?

  Mass divided by volume
• What clues indicate a chemical change?

  1 Change of colour

  2 change of odour

  3 formation of bubbles or gas

  4 formation of solid or precipitate

  5 energy given off in light or heat
• What is a characteristic property?

  A property that can be used to identify a substance.
• What are the characteristic properties?

  1 Freezing point

  2 Melting point

  3 Boiling point

  4 Density
• Who thought that the Atom was tiny, indivisible particles that were always in motion?

  Greek philosopher, Democritus.
• What information does the Periodic Table contain?

  Element Symbols, Atomic numbers, Atomic mass, Group or family, Periods, and Element categories.
• What are the types of elements?

  1 Metals

  2 Non-metals

  3 Metalloids
• What are the characteristic properties of metals?

  1 Shiny

  2 good conductivity

  3 solid

  4 malleable & ductile

  5 reacts with acids
• What are the characteristic properties of non-metals?

  1 Gases

  2 dull lustre

  3 brittle

  4 poor conductivity
• What are the characteristic properties of metalloids?

  1 properties from both metals & non-metals

  2 solid

  3 metallic appearance

  4 fair conductors

  5 chemically behave mostly as non-metals

  6 Can form Alloys
• How are the elements on the Periodic Table organized?

  By atomic numbers
• What is the organization of the Periodic Table?

  Periods and groups: Both numbered 1 to 18

  Families (groups) tend to have very similar physical & chemical properties.
• What patterns are apparent in the periodic table?

  1 Atomic mass increases from left to right across a period and top to bottom going down a group.

  2 Atomic size increases from right to left across a period and top to bottom going down a group.
• What is a chemical formula?


  A notation used to represent the type & number of atoms in a chemical compound.
• What are the chemical formulas of common everyday substances?

  Water: H2O Salt: NaCl Sugar: C12H22O11 Oxygen gas: O2 Carbon dioxide: CO2
• What is a molecule?


  A group of 2 or more atoms of the same element chemically bonded together. Also called "Diatomic elements".
• What are the 7 diatomic elements?

  Hydrogen, Nitrogen, Fluorine, Oxygen, Iodine, Chlorine, Bromine
• What is a compound?

  A compound consists of 2 or more different elements. Usually formed between 2 non-metals.

  Examples: H20, C02
• What types of bonds can form between atoms?

  Covalent & Ionic
• What are the characteristic properties of Covalent bonds?

  1 Tend to be gases, liquids, or soft solids

  2 Contain carbon & hydrogen

  3 Bonds are weaker than Ionic compounds

  4 Low melting points

  5 Not good conductors
• What are the characteristic properties of Ionic bonds?

  1 Strong bonds

  2 Opposite charges on the ions attract each other

  3 Ions come together in groups & form crystals

  4 Crystals have very high melting points
• how has our understanding of the atom changed overtime?

  answer:

  
• how do you represent Atoms and their subatomic particles?

  answer: