SNC 1W1 - Grade 9 Chemistry Unit Review 

• Atomic Structure: Understanding protons, neutrons, and electrons, and their roles in defining elements.

• Periodic Table: Familiarity with groups, periods, and key trends such as electronegativity and atomic radius.

• Chemical Bonds: Distinction between ionic, covalent, and metallic bonds, including examples of each.

• Chemical Reactions: Types of reactions (synthesis, decomposition, single replacement, double replacement), balancing equations, and conservation of mass.

• Acids and Bases: Properties, pH scale, and neutralization reactions.

Matter and Change

1. What is matter? Anything that takes up space and has mass.

2. Define and give examples of physical and chemical properties and changes.  What is the difference between a qualitative and a quantitative property?  Chemical = alteration of a substance into one or more different substances with different properties; Physical = no change in composition, only state or form. Qualitative = can observe with senses, not measured; quantitative = measured and has a numeric value

3. List five clues that might prove a chemical reaction has occurred.

Gas formed, precipitate formed, change in colour or odour, heat or light produced, difficult to reverse, new substance formed

4. Identify each of the following as a physical change (P) or chemical change (C) and give a reason.

5. Give an example of how the properties of matter help to determine an element or compound’s usefulness in human applications.  e.g. the bottom of frying pans are made of copper to conduct the heat to the food.

Choose an element or compound and describe one negative societal or environmental impact of its use. from your element research or reading assignment about Chemical Valley, diamond mining, road salt, or text questions.

Elements and Compounds

6. State whether each of the following pure substances is an element or compound.

a. Clear, colourless liquid that can be split into 2 gases, each with different properties. Compound (water)

b. A yellow solid always has the same properties and cannot be broken down by any means. Element (sulfur)

c. A colourless gas burns to produce carbon dioxide and water. Compound (fuel like propane)

7. Complete the following chart about subatomic particles.

8. Describe the similarities and differences between each pair of terms.

1. mixture, solution ; b.  element, compound ; c.  heterogeneous, homogeneous

mixture, solution – see different parts in a mixture, only one phase in a solution … give eg’s

element, compound– both pure substances; element is one type of particle, compound has >1… give eg’s

heterogeneous, homogeneous– see different parts in heterogeneous, only one phase in homogeneous .. eg’s

Models for Atoms

9. Review the models of the atom proposed by Dalton, J.J. Thomson, Rutherford, Chadwick and Bohr.  Be able to describe the main idea of his theory and how he demonstrated or proved it. See handout and text 6.6

10. Complete the following element chart.

11. Vinegar is a compound.  The chemical formula for vinegar is CH₃COOH. What elements are involved and how many of each are there? hydrogen -4 ; carbon – 2; oxygen -2

12.  Complete the following table: Only put in Yes for the columns that apply, leave the others blank.

13. Draw a Bohr-Rutherford diagram for the following: Mg,   Mg²⁺,   Ar   see Bohr-Rutherford assignment; Mg²⁺ has lost its 2 outermost valence electrons and show the ²⁺ beside the Mg symbol in the standard atomic notation

The Periodic Table

14. Groups:  

1. In what group are the noble gases found on the periodic table? 18

2. In what group are the alkali metals found on the periodic table?  1

3. In what group are the halogens found on the periodic table? 17

4. Give an example of an alkaline earth metal. beryllium

5. Describe the reactivity of the following groups of elements:

i) noble gases – reactive or non-reactive; why? Non-reactive, stable, has a full outermost/valence energy level/orbit____

ii) alkali metals – reactive or non-reactive; why? reactive, only 1 valence electron so it is easy to lose it and combine with a non-metal___________

iii) halogens – reactive or non-reactive; why? reactive, 7 valence electrons, 1 short of full valence so it is easy to gain one electron to become stable, like the noble gases__

Compare and contrast metals, non-metals and metalloids. see chart in notes