HESI A2 Chemistry Practice Questions

Questions 25

HESI A2

HESI A2 Test Bank

HESI A2 Chemistry Practice Questions Questions

Question 1 of 5

What is the oxidation state of the potassium ion in the compound KCl?

Correct Answer: A

Rationale: The correct answer is A: +1. In KCl, potassium is a group 1 element, which always has an oxidation state of +1 in its compounds. Chlorine, a group 17 element, has an oxidation state of -1 in most compounds. Therefore, the oxidation state of potassium in KCl must be +1 to balance the -1 oxidation state of chlorine. Choices B, C, and D are incorrect because they do not align with the known oxidation states of potassium and chlorine in this compound.

Question 2 of 5

How many neutrons are in an atom of helium-4?

Correct Answer: A

Rationale: The correct answer is A: 2. Helium-4 has an atomic number of 2, which represents the number of protons in its nucleus. Since the atomic number is the sum of protons and neutrons, and helium-4 has 2 protons, it must also have 2 neutrons to make the total atomic mass 4. Therefore, there are 2 neutrons in an atom of helium-4. Choice B: 3 is incorrect because it does not match the atomic number of helium-4. Choice C: 4 is incorrect as it is the total atomic mass of helium-4, not the number of neutrons. Choice D: 6 is incorrect as it does not correspond to the atomic structure of helium-4.

Question 3 of 5

On the periodic table, families of elements with similar properties appear in the same _________.

Correct Answer: D

Rationale: The correct answer is D: column. Elements in the same column of the periodic table, also known as groups, have similar properties due to the same number of valence electrons. This similarity is a result of the elements' electronic configuration, leading to comparable chemical behavior. In contrast, rows (choice A) represent periods, indicating elements with increasing atomic numbers but not necessarily similar properties. Principal energy levels (choice B) are related to the energy levels of electrons in an atom, not the grouping of elements. Choice C, period, refers to elements arranged horizontally on the periodic table, which do not share the same properties as elements in the same column.

Question 4 of 5

Which one is not a hydrocarbon?

Correct Answer: B

Rationale: The correct answer is B: Pyridine (C5H5N) because it is not a hydrocarbon. Hydrocarbons are compounds composed of only carbon and hydrogen atoms. Pyridine contains nitrogen in addition to carbon and hydrogen, making it a heterocyclic compound. Methane, ethane, and propane are all hydrocarbons as they only contain carbon and hydrogen atoms. Pyridine is not a hydrocarbon as it contains nitrogen in its chemical structure, making it the only non-hydrocarbon option among the choices.

Question 5 of 5

Cobalt-60 has a half-life of 5 years. If you start with 20 g of cobalt-60, how much is left after 10 years?

Correct Answer: C

Rationale: The correct answer is C: 5 g. After 10 years, half of the cobalt-60 decays, leaving 10 g. After 5 more years, another half will decay, leaving 5 g. This is because the half-life of cobalt-60 is 5 years, meaning it takes 5 years for half of the initial amount to decay. Choices A, B, and D are incorrect because they do not take into account the concept of half-life and the exponential decay of radioactive substances.

Similar Questions

Join Our Community Today!

Join Over 10,000+ nursing students using Nurselytic. Access Comprehensive study Guides curriculum for HESI A2-HESI A2 and 3000+ practice questions to help you pass your HESI A2-HESI A2 exam.

Call to Action Image