TEAS 7 Chemistry: Essential Practice for Success

ATI TEAS 7

Chemistry

1. Why are noble gas elements generally unreactive?

A. They are too large and cannot form bonds easily.
B. They lack valence electrons in their outermost shell.
C. They have strong bonds within their own molecules.
D. They have already achieved stable electron configurations.

Correct answer: D

Rationale: They have already achieved stable electron configurations. With completely filled outermost shells, noble gas elements have no need to gain or lose electrons, minimizing their tendency to participate in chemical reactions.

2. The phenomenon responsible for the creation of rainbows is:

A. Reflection only
B. Diffraction
C. Refraction and reflection
D. Polarization

Correct answer: C

Rationale: The correct answer is C: Refraction and reflection. Rainbows are formed when sunlight is refracted and reflected inside raindrops. The sunlight entering the raindrop is refracted, then internally reflected off the back surface of the droplet, and finally refracted again as it exits the droplet. This dispersion of light causes the separation of colors we see in a rainbow. Reflection alone (option A) does not account for the formation of rainbows. Diffraction (option B) is the bending of light around obstacles, not the main mechanism behind rainbows. Polarization (option D) refers to the orientation of light waves, which is not the primary process involved in creating rainbows.

3. Which of the following is an example of a commensal relationship between a microorganism and a human?

A. Salmonella causing food poisoning
B. taphylococcus aureus causing skin infections
C. coli living in the gut
D. Rabies virus causing neurological disease

Correct answer: C

Rationale: Rationale: A commensal relationship is a type of symbiotic relationship in which one organism benefits, while the other is neither harmed nor benefited. In this case, E. coli living in the gut is an example of a commensal relationship because it can benefit from the environment in the gut without causing harm to the human host. Option A, Salmonella causing food poisoning, is an example of a pathogenic relationship where the microorganism causes harm to the host. Option B, Staphylococcus aureus causing skin infections, is also an example of a pathogenic relationship where the microorganism causes harm to the host. Option D, Rabies virus causing neurological disease, is another example of a pathogenic relationship where the microorganism causes harm to the host.

4. What are isotopes?

A. Atoms of the same element with different numbers of protons.
B. Atoms of the same element with different numbers of neutrons.
C. Atoms of different elements with the same number of protons.
D. Atoms of different elements with the same number of electrons.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means that isotopes have the same atomic number (Z) but different mass numbers (A). For example, carbon-12 (Â¹Â²C), carbon-13 (Â¹Â³C), and carbon-14 (Â¹â´C) are all isotopes of carbon. They all have six protons in their nuclei, but they have different numbers of neutrons: carbon-12 has six neutrons, carbon-13 has seven neutrons, and carbon-14 has eight neutrons.

5. Recognize the opposing muscle pair.

A. Bicep and tricep (Arm flexion and extension)
B. Hamstring and quadriceps (Knee extension and flexion)
C. Pectoralis major and pectoralis minor (Chest muscles)
D. Trapezius and deltoid (Shoulder movement)

Correct answer: A

Rationale: The bicep and tricep muscles are antagonistic muscle pairs, meaning they work in opposition to each other. The bicep is located on the front of the upper arm and is responsible for flexing the elbow joint. The tricep is located on the back of the upper arm and is responsible for extending the elbow joint.