Gr.9 Review

• The human body contains enough carbon to provide “lead” (graphite) for approximately 9000 pencils.
• Physical properties and changes are different from chemical changes in a way that clues of a chemical change can be identified.
• The charges and locations of the three subatomic particles (p, e and n) can be calculated for each: p= atomic #, e = protons (in atoms), n= atomic mass - atomic #.
• The periodic table should be understood with terms such as Period, Family, Alkali Earth metals, Alkaline Earth metals, Transition Metal, Halogens, Noble Gases, Metals, Non-metals, Metalloids.
• Bohr-Rutherford Diagram can be drawn for the first 20 elements.
• Lewis-dot diagrams for an Atom can be drawn for the first 20 elements.
• Counting Atoms can be done to determine the number of atoms present in a compound.
• Everything around us is made up of matter, which includes solids, liquids, and gases.
• Matter is classified into pure substances, mixtures, compounds, elements, solutions, heterogeneous mixtures.
• Elements are pure substances that contain only one kind of atom, represented on the Periodic Table.
• Elements are the building blocks for all other substances, a small number of types of brick can be used to create an enormous range of different buildings.
• In much the same way a small number of elements can give rise to an enormous number of compounds, a small number of different types of Lego Brick can be used to create a huge number of different models.
• Compounds are pure substances that contain two or more different elements in a fixed proportion, they can be identified with a chemical formula.
• Examples of compounds include Carbon dioxide (CO2) and Sodium chloride (NaCl).