Chemistry Final Exam

This exam consists of three sections: Multiple Choice, Short Answer, and Extended Response/Scenario Analysis. Read all instructions carefully and answer each question as directed. Manage your time according to the suggested time limits for each section.

Section A: Multiple Choice (20 minutes) Choose the best answer for each question.

A scientist is choosing between two elements:

• Element X: Group 1, Period 3
• Element Y: Group 17, Period 3 Which prediction is BEST supported?

A reaction produces a solid precipitate when two solutions are mixed. What is the best explanation?

A student measures mass before and after a reaction in a sealed container and finds it unchanged. What claim is BEST supported?

Which element would have the largest atomic radius?

Which element is most likely to form a +1 ion?

Which best explains why noble gases are unreactive?

A compound conducts electricity when dissolved in water but not as a solid. What type of bonding is present?

Which process requires energy?

Which type of bonding involves the sharing of electrons?

Which substance would likely have the highest melting point?

What happens during nuclear fusion?

Which statement best describes electronegativity?

Section B: Short Answer (25 minutes) Answer each question clearly and completely.

Explain why atomic radius increases as you move down a group on the periodic table.

Magnesium reacts with chlorine.

• Identify the ions formed
• Write the chemical formula
• Explain how the ratio is determined

A reaction releases energy.

Explain this in terms of:

• Bonds broken
• Bonds formed

Explain why ionic compounds conduct electricity when dissolved in water but not when solid.

Section C Scenario: Designing a New Material A company is designing a material for use in extreme environments. They are considering:

• Substance A: Metal + nonmetal
• Substance B: Nonmetal + nonmetal
• Substance C: Network covalent structure You are hired to evaluate these options.

Part 1: Bonding Analysis

• Identify the bonding type for each substance
• Explain how electron behavior determines the bonding

Part 2: Property Prediction For each substance, predict:

• Melting point
• Electrical conductivity
• Structural strength Justify your answers using bonding and forces.

Part 3: Energy Explanation One reaction forming Substance B releases energy. Explain why using bond energy concepts.

Part 4: Decision Which substance is BEST for:

• High heat environments
• Electrical applications Defend your choices with clear scientific reasoning.

Section 7: Cross-Unit Transfer Task (Written) A newly discovered substance, Compound X, has the following properties:

• High melting point (above 800°C)
• Conducts electricity when dissolved in water, but not as a solid
• Forms from a metal and a nonmetal
• Dissolving the compound in water releases energy (the solution warms up)

Part A: Bond Type Identify the most likely type of bonding in Compound X. Then, justify your answer using at least two pieces of evidence.

Part B: Periodic Trends

• Predict the relative electronegativity difference
• Describe where elements are located on the periodic table
• Explain how trends support bonding

Part C: Energy Behavior Explain why energy is released when the compound dissolves. Include:

• Particle interactions
• Role of forces
• Why energy is released

Part D: Scientific Claim A scientist claims Compound X is covalent. Do you agree or disagree? Defend your answer.