which of the following distinguishes the isotopes of an element

ATI TEAS 7

TEAS 7 Science Practice Test

1. Which of the following distinguishes the isotopes of an element?

A. Isotopes are atoms of the same element that have different ionic charges.
B. Isotopes are atoms of elements within the same group on the periodic table.
C. Isotopes are atoms of the same element that have different numbers of neutrons.
D. Isotopes are atoms of the same element with different electron configurations.

Correct answer: C

Rationale: Isotopes are defined as atoms of the same element that have the same number of protons in their nucleus but different numbers of neutrons. This leads to variations in atomic mass for isotopes of an element. The different number of neutrons in isotopes results in differences in their atomic mass and properties while still belonging to the same element. Choice A is incorrect because isotopes do not have different ionic charges, they have the same chemical properties. Choice B is incorrect because isotopes are not atoms of elements within the same group on the periodic table; they are variants of the same element. Choice D is incorrect because isotopes of an element have the same electron configuration, differing only in the number of neutrons in the nucleus.

2. What is the primary mode of CO2 transport in the body?

A. Bicarbonate
B. Carbamino compounds
C. None of these
D. Plasma

Correct answer: A

Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.

3. What is the term for the gradual loss of topsoil due to wind or water erosion?

A. Desertification
B. Leaching
C. Salinization
D. Acidification

Correct answer: A

Rationale: A) Desertification is the correct term for the gradual loss of topsoil due to wind or water erosion. It refers to the process by which fertile land becomes desert, usually due to factors like drought, deforestation, or inappropriate agriculture practices. This process can lead to the degradation of land and contribute to the expansion of deserts. B) Leaching is the process in which minerals are washed out of the soil by water moving downwards through it. This is different from the loss of topsoil due to erosion. C) Salinization occurs when salt accumulates in the soil, typically as a result of irrigation in arid regions. While salinization affects soil quality, it is not specifically related to the gradual loss of topsoil due to erosion. D) Acidification refers to the decrease in soil pH, often caused by factors like acid rain or the use of acidic fertilizers. This process is distinct from the gradual loss of topsoil due to erosion.

4. In the process of osmosis, the solvent moves from an area of...

A. Low solute concentration to high solute concentration
B. Hotter solution to colder solution
C. Colder solution to hotter solution
D. High solute concentration to low solute concentration

Correct answer: D

Rationale: In the process of osmosis, solvent molecules move from an area of high solute concentration to low solute concentration. This movement occurs to equalize the solute concentrations on both sides of the semi-permeable membrane. As water tends to move towards higher solute concentrations, the solvent moves in this direction to balance the concentrations and establish equilibrium. Choices A, B, and C are incorrect because osmosis involves the movement of solvent, not solute, and it moves towards the area of higher solute concentration, not lower. Therefore, the correct answer is option D.

5. Which property of matter refers to the force of gravity acting on an object?

A. Mass
B. Weight
C. Density
D. Volume

Correct answer: B

Rationale: Weight is the property of matter that refers to the force of gravity acting on an object. Mass is the amount of matter in an object, not affected by gravity. Density is the mass per unit volume of a substance, not directly related to gravity. Volume is the amount of space that an object occupies, not a measure of gravity's force.