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: Which of the following sequences on a DNA molecule would be complementary to GCTTATAT?

A. TAGGCGCG

B. ATCCGCGC

C. CGAATATA

D. TGCCTCTC

Answer Explanation
Q #2: Metabolism of proteins Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?

A. Sebum

B. Urea

C. Lysozymes

D. Water

Answer Explanation

Proteins are nitrogen-based compounds, which when broken down release ammonia. Ammonia is a toxic substance to the body, and sebaceous glands coverts it to urea.
Q #3: Which of these organs is not considered an accessory digestive structure?

A. mouth

B. salivary glands

C. pancreas

D. liver

Answer Explanation

Accessory organs of the digestive system comprise of organs that empty secretions into the alimentary canal. These organs include salivary glands, liver, gallbladder and pancreas. The mount if path of the alimentary canal.

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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: Which of the following sequences on a DNA molecule would be complementary to GCTTATAT?

Answer Explanation

Q #2: Metabolism of proteins Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?

Answer Explanation

Q #3: Which of these organs is not considered an accessory digestive structure?

Answer Explanation

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