Grade 10 Science Exam Notes

Grade 10 Science Exam Study Note
Chemistry – Pg1, Biology – Pg11, Optics/Light – Pg 20

Chemistry
Physical and chemical properties and changes
• Physical Properties: Something you can see or observe with your senses o State o Colour o Size o Luster/Shinyness o Smell o Melting/Boiling Points o Solubility o Viscosity o Density
• Chemical Properties: Characteristics used in a chemical reaction o Tendency to React o Combustibility o Tendency to Rust
• Physical Changes o Easily reversible o Doesn’t change the substance o Only changes physical properties
• Chemical Changes o Creates new substance o Usually irreversible o Can change physical properties in addition to changing chemical ones
Evidence of chemical changes:
• Change in colour
• Heat or light produced
• Production of gas bubbles
• Precipitate formed
• Change in smell
Patterns and the Periodic Table o Periods: The rows of the table that refer to the number of orbits o Groups: The columns of the table that indicate the number of valence electrons
 1st Group Alkaline Metals: Very reactive due to having only 1 valence electron (Lithium, Potassium)
 2nd Group Alkali Earth Metals: Quite reactive due to only having 2 valence electrons (Calcium, Magnesium)
 3-6 Group Metalloids: Semi reactive, have traits of both metals and non metals (silicon, boron)
 4-6 Group Other Non-Metals: Broad characteristics, can create molecular compounds (Oxygen, nitrogen, carbon)
 7th Group Halogens: Very reactive due to having only 1 less than a full shell (Flourine, Chlorine)
 8th Group Noble Gases: Not reactive due to having a full shell (Argon, Neon, Helium) o Cations are Positive Ions o Anions are Negative Ions
• Lewis dot diagrams
• Electron arrangements and reactivity. Explain why alkali metals are highly reactive. o Electrons are arranged into shells as are shown in the Bohr-Rutherford diagrams right. Lithium (Li-7) has only one electron in it’s outermost shell (one valence