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 hormone, produced by the ovaries, is responsible for the development of the uterine lining during the menstrual cycle and supports early pregnancy?

A. Estrogen
B. Progesterone
C. Testosterone
D. Prolactin

Correct answer: B

Rationale: Progesterone, produced by the ovaries, is responsible for the development of the uterine lining during the menstrual cycle and supports early pregnancy. While estrogen also plays a crucial role in the menstrual cycle, progesterone is specifically known for its role in preparing the uterus for pregnancy and maintaining the uterine lining. Testosterone is primarily a male sex hormone and not directly involved in these processes. Prolactin is a hormone that is mainly associated with milk production and not related to the development of the uterine lining or early pregnancy.

3. Which of the following is a chief difference between evaporation and boiling?

A. Liquids boil only at the surface, while they evaporate equally throughout the liquid.
B. Evaporating substances change from liquid to gas, while boiling substances change from gas to liquid.
C. Evaporation can happen below a liquid's boiling point.
D. Evaporation happens in nature, while boiling is a man-made phenomenon.

Correct answer: C

Rationale: The chief difference between evaporation and boiling is that evaporation can happen below a liquid's boiling point, while boiling only occurs at the liquid's boiling point. Evaporation is the process of a liquid turning into a gas at any temperature, while boiling specifically refers to the rapid vaporization that occurs when a liquid reaches its boiling point. Choice A is incorrect because liquids evaporate throughout the liquid, not just at the surface. Choice B is incorrect as evaporating substances change from liquid to gas, while boiling substances change from liquid to gas. Choice C is incorrect as boiling is not a man-made phenomenon; in fact, it is a natural process based on temperature changes. Choice D is incorrect because evaporation can happen naturally and is not limited to man-made processes.

4. Balance the following redox reaction in acidic solution: I⁻ (aq) + Cr₂O₇²⁻ (aq) -> I₂ (aq) + Cr³⁺ (aq). Identify the oxidizing agent and reducing agent.

A. I⁻ is oxidized, Cr₂O₇²⁻ is reduced
B. I⁻ is reduced, Cr₂O₇²⁻ is oxidized
C. Both I⁻ and Cr₂O₇²⁻ are oxidized
D. Both I⁻ and Cr₂O₇²⁻ are reduced

Correct answer: B

Rationale: In the given redox reaction, I⁻ is gaining electrons to form I₂, which means I⁻ is being reduced (undergoing reduction). On the other hand, Cr₂O₇²⁻ is losing electrons to form Cr³⁺, indicating that Cr₂O₇²⁻ is being oxidized (undergoing oxidation). Therefore, I⁻ is the reducing agent and Cr₂O₇²⁻ is the oxidizing agent. Choice A is incorrect because I⁻ is being reduced, not oxidized. Choice C is incorrect as both species cannot be oxidized in the same reaction. Choice D is incorrect as both species cannot be reduced in the same reaction.

5. What does the concept of punctuated equilibrium suggest?

A. Evolution occurs gradually through the continuous accumulation of small changes over long periods.
B. Evolution is characterized by long periods of relative stasis punctuated by rapid bursts of evolutionary change.
C. The fossil record is a complete and accurate representation of all past life forms.
D. Natural selection primarily favors extreme phenotypes within a population.

Correct answer: B

Rationale: Punctuated equilibrium suggests that evolution is characterized by long periods of relative stasis punctuated by rapid bursts of evolutionary change. This concept, proposed by Stephen Jay Gould and Niles Eldredge, implies that species remain relatively unchanged for extended periods, followed by sudden bursts of rapid evolution. Option A describes the gradualism model, which is different from punctuated equilibrium. Option C is inaccurate as the fossil record is incomplete and biased. Option D is unrelated to the concept of punctuated equilibrium.