how many neutrons are in an atom of helium 4

HESI A2

HESI A2 Chemistry Practice Questions

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

A. 2
B. 3
C. 4
D. 6

Correct answer: A

Rationale: The atomic number of helium is 2, indicating it has 2 protons. Helium-4, the most common isotope of helium, has 2 neutrons in addition to its 2 protons. Therefore, the correct answer is 2 neutrons in an atom of helium-4. Choice B, C, and D are incorrect as they do not match the correct composition of helium-4, which consists of 2 protons and 2 neutrons.

2. What are proteins made up of?

A. Fatty acids
B. Amino acids
C. Nucleotides
D. Sugars

Correct answer: B

Rationale: Proteins are made up of amino acids. Amino acids are the building blocks of proteins, essential for various biological processes in the body such as enzyme function, transport, and structural support. Fatty acids (Choice A) are components of lipids, not proteins. Nucleotides (Choice C) are the building blocks of nucleic acids like DNA and RNA, not proteins. Sugars (Choice D) are carbohydrates and are not the primary components of proteins.

3. What is the name of the negatively charged subatomic particles?

A. Protons
B. Neutrons
C. Electrons
D. Isotopes

Correct answer: C

Rationale: The correct answer is C: Electrons. Electrons are the negatively charged subatomic particles. They are found outside the atomic nucleus and carry a negative charge. Protons are positively charged particles found in the nucleus, neutrons have no charge, and isotopes are atoms of the same element with different numbers of neutrons, not subatomic particles.

4. How many electrons are in a neutral atom of neon?

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

Correct answer: B

Rationale: The atomic number of neon is 10, which represents the number of protons in its nucleus. In a neutral atom, the number of electrons is equal to the number of protons to maintain electrical neutrality. Therefore, a neutral atom of neon contains 10 electrons, matching the 10 protons within the nucleus. Choice A (9 electrons) is incorrect as it doesn't correspond to the atomic number of neon. Choices C (11 electrons) and D (12 electrons) are also incorrect as they do not align with the correct atomic number of neon.

5. What is the charge of a beta particle?

A. -1
B. +1
C. +2
D. No charge

Correct answer: A

Rationale: A beta particle has a charge of -1. Beta particles are high-energy, high-speed electrons emitted during radioactive decay processes. Since electrons carry a charge of -1, beta particles also carry a charge of -1. This negative charge indicates that beta particles are negatively charged. Option B is incorrect as it suggests a positive charge, which is not the case for beta particles. Option C is incorrect as it indicates a higher positive charge, which is not true for beta particles. Option D is incorrect as beta particles do have a charge, which is negative.