Lithium has an atomic number of 3 and a mass number of 7. Which of the following is the number of neutrons in a lithium atom?

A. 4

B. 7

C. 12

D. 3

Answer Explanation:

The atom is identified by the atomic number in the periodic table. The atomic number is equal to the number of protons and mass number is the sum of the number of protons and neutrons in the nucleus of an atom. Thus, to find how many neutrons are in lithium atom we use the formula below.

Mass number = number of protons + number of neutrons.

Letting n be number of neutrons in the lithium atom, we have

7=3+n

Rearranging the above equation

3+n=7

n=7-3

n=4

Thus, lithium atom has 4 neutrons.

Therefore, the Correct Answer is A.

Q #1: The ________ circulation picks up oxygen for cellular use and drops off carbon dioxide for removal from the body.

A. pulmonary

B. interlobular

C. respiratory

D. bronchial
Answer Explanation

Our blood flow is separated into two major pathways, listed below:
1. Systemic circulation - this comes from the left side of the heart and pumps blood to all working tissues, including the brain, muscle, heart, and other organs, and then into the right side of the heart.
2. Pulmonary system - this comes from the right side of the heart, and pumps blood to the alveolar sacs within the lungs, and then into the left side of the heart
In pulmonary circulation: The pulmonary artery is a big artery that comes from the heart. It splits into two main branches, and brings blood from the heart to the lungs. At the lungs, the blood picks up oxygen and drops off carbon dioxide.
Q #2: The Life Cycle of HIV Which of the following allows the AIDS virus, which contains RNA, to insert viral DNA into the DNA of a host T-cell after the AIDS virus enters the cell?

A. Receptor proteins located on the surface of the virus

B. The protein that makes up the capsid of the virus

C. Reverse transcriptase, an enzyme encoded by the virus

D. The phospholipids found on the envelope of the virus

Answer Explanation

The AIDS virus (HIV virus) is Class VI or Group VI in the Baltimore Classification. Based on the Baltimore Classification, this specifically involves the reverse transcriptase enzyme and it is encoded by the virus.

This is the enzyme that will produce DNA molecules from the viral RNA. This is the mechanism involved where it will use the reverse transcriptase enzyme to insert viral DNA into the genetic material of the host cell.
Q #3: Which of the following vessels carries oxygenated blood?

A. Inferior vena cava

B. Pulmonary vein

C. Pulmonary artery

D. Superior vena cava

Answer Explanation

Pulmonary vein carries oxygenated blood from the lungs to the heart. Pulmonary artery carries deoxygenated blood from the heart to the lungs.
Superior and inferior vena cava bring in deoxygenated blood from all other parts of the body to the heart.

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Lithium has an atomic number of 3 and a mass number of 7. Which of the following is the number of neutrons in a lithium atom?

More Questions on TEAS 7 Science

Q #1: The ________ circulation picks up oxygen for cellular use and drops off carbon dioxide for removal from the body.

Answer Explanation

Q #2: The Life Cycle of HIV Which of the following allows the AIDS virus, which contains RNA, to insert viral DNA into the DNA of a host T-cell after the AIDS virus enters the cell?

Answer Explanation

Q #3: Which of the following vessels carries oxygenated blood?

Answer Explanation

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