what is the electron configuration of an atom

ATI TEAS 7

TEAS 7 science practice questions

1. What does the term 'electron configuration' refer to in relation to an atom?

A. The arrangement of electrons in an atom's orbitals.
B. The number of protons in an atom's nucleus.
C. The number of neutrons in an atom's nucleus.
D. The number of electrons in an atom's valence shell.

Correct answer: A

Rationale: The electron configuration of an atom refers to the arrangement of electrons in the atom's orbitals. This arrangement determines the atom's chemical properties and behavior. The number of protons in an atom's nucleus (option B) is known as the atomic number, which defines the element. The number of neutrons in an atom's nucleus (option C) contributes to the atom's mass number. The number of electrons in an atom's valence shell (option D) is important for understanding the atom's reactivity and bonding behavior, but the electron configuration specifically refers to how electrons are distributed among the different orbitals in an atom.

2. Which type of cell division is responsible for sexual reproduction?

A. Mitosis
B. Meiosis
C. Amitosis
D. Cytokinesis

Correct answer: B

Rationale: Meiosis is the type of cell division responsible for sexual reproduction. During meiosis, a single cell undergoes two rounds of division to produce four daughter cells, each with half the number of chromosomes as the parent cell. This reduction in chromosome number is essential for sexual reproduction as it ensures that when two gametes (sperm and egg) combine during fertilization, the resulting zygote will have the correct number of chromosomes. Mitosis, on the other hand, is a type of cell division that produces two daughter cells with the same number of chromosomes as the parent cell and is involved in growth, repair, and asexual reproduction. Amitosis is a rare form of cell division that does not involve the typical processes of mitosis or meiosis. Cytokinesis is the process of dividing the cytoplasm of a cell after mitosis or meiosis.

3. Which of the following components is found in DNA?

A. Uracil
B. Deoxyribose
C. Guanine
D. Phosphate group

Correct answer: B

Rationale: The correct answer is B: Deoxyribose. DNA is composed of nucleotides containing deoxyribose sugar, phosphate group, and nitrogenous bases (adenine, thymine, guanine, and cytosine). Deoxyribose is the sugar component specific to DNA, while ribose is found in RNA. Guanine (choice C) is a nitrogenous base present in both DNA and RNA. Uracil (choice A) is a nitrogenous base specific to RNA, replacing thymine found in DNA. The phosphate group (choice D) is an essential part of nucleotides in both DNA and RNA, providing the backbone structure for the nucleic acid chains.

4. A person pushes a box across a floor with a constant force. The box eventually comes to a stop due to friction. What happens to the work done by the person?

A. It increases as the box moves further.
B. It decreases as the box slows down.
C. It remains constant throughout the motion.
D. It becomes zero once the box stops.

Correct answer: D

Rationale: Work done is defined as the product of the force applied and the distance moved in the direction of the force. In this scenario, when the box comes to a stop, the displacement becomes zero, leading to zero work done by the person. Choice A is incorrect as the work done is not increasing, but rather decreasing as the box slows down. Choice B is incorrect because the work done does not decrease as the box slows down; it becomes zero when the box stops. Choice C is incorrect as the work done is not constant but decreases to zero when the box stops.

5. In nuclear physics, the term 'barn' is a unit commonly used to quantify:

A. Energy
B. Radioactivity
C. Nuclear cross-section
D. Half-life

Correct answer: C

Rationale: In nuclear physics, the term 'barn' is a unit used to quantify nuclear cross-section. Nuclear cross-section is a measure of the probability of a nuclear reaction occurring when an atomic nucleus interacts with a particle or another nucleus. The barn is a unit of area equal to 10^-28 square meters; it is commonly used to describe the cross-sectional area of atomic nuclei for nuclear reactions. Choice A, 'Energy,' is incorrect because a barn is not a unit for measuring energy; it is a unit of area. Choice B, 'Radioactivity,' is incorrect as radioactivity is typically measured in units like becquerels. Choice D, 'Half-life,' is also incorrect as half-life is a measure of the time it takes for half of a substance to decay, not related to the concept of a barn as a unit of nuclear cross-section.