GED Sample Questions: Chemistry/Science Questions

By Murray Shukyn, Dale E. Shuttleworth, Achim K. Krull

For the Science portion of the GED, you will be expected to have a working knowledge of Chemistry that is equivalent to that of a high school student. Look at the following example to see the type of question you might find on test day.

The questions in this article refer to the following passage.


Isotopes are chemical cousins. They are related to each other, but each isotope has slightly different — but related — atoms. Each of the related atoms has the same number of protons but a different number of neutrons. Because the number of electrons or protons determines the atomic number, isotopes have the same atomic number.

The number of neutrons determines the mass number. Because the number of neutrons in each isotope is different, the mass number is also different. These cousins all have different mass numbers but the same atomic number. Their chemical properties are similar but not the same. Like most cousins, they have family resemblances, but each has a unique personality.

  1. Different elements would have different numbers of ____________.

  2. Isotopes of a chemical have the same

    • (A)number of neutrons

    • (B)mass number

    • (C)atomic number

  3. A scientist has found related atoms in two different substances. If both atoms have the same atomic number but different mass numbers, what preliminary conclusion can be reached about the atoms?

    • (A)They are the same substance.

    • (B)They are isotopes.

    • (C)They are different substances.

    • (D)One is a compound of the other.

Answer Key

  1. protons.

    According to the first sentence of the passage, the atomic number is determined by the number of protons. Skimming the paragraph after reading the question for key words in the question makes choosing the correct answer faster and easier.

  2. C. atomic number.

    The last sentence of the first paragraph of the passage states that isotopes have the same atomic number.

  3. B. They are isotopes.

    The last sentence of the first paragraph of the passage states that isotopes have the same atomic number. The second sentence of the second paragraph tells you that isotopes have different mass numbers. This question requires using two bits of information from two different locations in the passage to decide on the right answer.