which gives the number of protons in the atomic nucleus of an alkali metal

HESI A2

Chemistry HESI A2 Practice Test

1. What is the number of protons in the atomic nucleus of an alkali metal?

A. 9
B. 10
C. 11
D. 12

Correct answer: C

Rationale: The number of protons in the atomic nucleus of an alkali metal is 11. Alkali metals, belonging to group 1 of the periodic table, have 1 electron in their outer shell, which corresponds to 1 proton in their nucleus. Therefore, the correct answer is option C: 11. Choice A (9) is incorrect because it does not match the number of protons in an alkali metal. Choice B (10) is incorrect as it is also not the correct number of protons for an alkali metal. Choice D (12) is incorrect as it is not the typical number of protons found in the nucleus of an alkali metal.

2. What is the chemical reaction that involves breaking down a compound into component parts?

A. Decomposition
B. Synthesis
C. Combustion
D. Single replacement

Correct answer: A

Rationale: Decomposition is the correct answer because in a decomposition reaction, a compound is broken down into simpler substances. This type of reaction involves the splitting of a compound into its component parts, often through the use of heat, light, or electricity. Synthesis (choice B) is the opposite process where simpler substances are combined to form a more complex compound. Combustion (choice C) is a reaction involving rapid oxidation often accompanied by heat and light. Single replacement (choice D) is a reaction where one element replaces another in a compound.

3. At what temperature does water boil in °F?

A. 210°F
B. 212°F
C. 215°F
D. 220°F

Correct answer: B

Rationale: Water boils at 212°F under standard atmospheric pressure. This is the point at which water changes from a liquid to a gas phase. Choice A (210°F) is incorrect as it is below the boiling point of water. Choice C (215°F) and Choice D (220°F) are also incorrect as they are above the boiling point of water.

4. Which gas is released during photosynthesis?

A. Carbon dioxide
B. Oxygen
C. Nitrogen
D. Helium

Correct answer: B

Rationale: During photosynthesis, plants utilize carbon dioxide and water to produce glucose and oxygen. Oxygen is released as a byproduct of this process, which is essential for the survival of most living organisms that depend on it for respiration. Therefore, the correct answer is oxygen. Choices A, C, and D are incorrect. Carbon dioxide is utilized in photosynthesis, nitrogen is not directly involved in the process, and helium is not a gas released during photosynthesis.

5. What are the three types of intermolecular forces?

A. Ionic, covalent, hydrogen
B. Hydrogen bonding, dipole interactions, dispersion forces
C. Van der Waals, ionic, covalent
D. Hydrogen, Van der Waals, dispersion forces

Correct answer: B

Rationale: The three types of intermolecular forces are hydrogen bonding, dipole interactions, and dispersion forces. Option A includes ionic and covalent bonds, which are intramolecular forces, not intermolecular. Option C includes van der Waals forces, which encompass dipole interactions and dispersion forces, but also includes ionic and covalent bonds. Option D is close but misses dipole interactions, which are distinct from hydrogen bonding and dispersion forces. Therefore, option B is the correct choice as it includes the three specific types of intermolecular forces.