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Atomic Structure Introduction Practice Tests

These Grade 8 Science practice tests cover atoms, nuclei, protons, neutrons, electrons, atomic number, mass number, isotopes, ions, valence electrons, energy levels, atomic models, and periodic-table patterns.

Skills covered

  • Identifying the location, charge, and role of protons, neutrons, and electrons
  • Using atomic number and mass number to determine atomic structure
  • Distinguishing isotopes, ions, cations, anions, elements, and compounds
  • Connecting valence electrons and energy levels to periodic-table patterns
  • Using evidence and models to explain how scientific ideas about atoms develop

How to use these practice tests

Start with the proton number because it identifies the element. Then use mass number to find neutrons and compare protons with electrons to determine charge. Use the periodic table and atomic models to check the result.

For more Grade 8 Science practice, return to the Grade 8 Science category.

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Grade 8 Atomic Structure Introduction Practice Tests

Practice Grade 8 Science questions about atoms, protons, neutrons, electrons, nuclei, atomic number, mass number, isotopes, ions, and periodic-table patterns.

Choose the best answer for each question. Use proton number, mass number, charge, electron arrangement, and periodic-table patterns to analyze atomic structure.

10 Questions
0/10 Questions0 %
Correct 0
Incorrect 0
Unanswered 10
1. QuestionMultiple choice

What is an isotope?

Please select an answer first.

Correct answer: A

The correct answer is An atom of the same element with a different number of neutrons.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

Isotopes have the same proton number but different neutron numbers.

2. QuestionMultiple choice

What is an ion?

Please select an answer first.

Correct answer: B

The correct answer is An atom or group of atoms with a net electric charge.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

An ion forms when the number of electrons does not equal the number of protons.

3. QuestionMultiple choice

What is a cation?

Please select an answer first.

Correct answer: C

The correct answer is A positively charged ion.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

A cation has more protons than electrons, giving it a positive net charge.

4. QuestionMultiple choice

What is an anion?

Please select an answer first.

Correct answer: D

The correct answer is A negatively charged ion.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

An anion has gained electrons and therefore has a negative net charge.

5. QuestionMultiple choice

How do two isotopes of the same element differ?

Please select an answer first.

Correct answer: A

The correct answer is They have different numbers of neutrons..

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

The proton number remains the same, while the neutron number changes between isotopes.

6. QuestionMultiple choice

What happens to an atom when it loses electrons?

Please select an answer first.

Correct answer: B

The correct answer is It becomes a positively charged ion..

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

Losing negative electrons leaves more positive proton charge than negative electron charge.

7. QuestionMultiple choice

Carbon-12 and carbon-14 are both carbon because they have the same number of what?

Please select an answer first.

Correct answer: C

The correct answer is Protons.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

Both names refer to carbon, so both atoms must have carbon atomic number and proton count.

8. QuestionMultiple choice

What happens when a neutral atom gains one electron?

Please select an answer first.

Correct answer: D

The correct answer is It becomes an ion with a negative one charge..

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

An additional negative electron gives the atom a net charge of negative one.

9. QuestionMultiple choice

Which particle number remains unchanged when an atom becomes an ion?

Please select an answer first.

Correct answer: A

The correct answer is The number of protons.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

Ion formation changes electrons, while proton number remains the identity of the element.

10. QuestionMultiple choice

An atom has 11 protons and 10 electrons. What is its net charge?

Please select an answer first.

Correct answer: B

The correct answer is Positive one.

  1. Identify the atomic information: Find the numbers of protons, neutrons, and electrons or identify the particle, model, element, isotope, or ion being described.
  2. Apply the relationship: Use atomic number for protons, mass number for protons plus neutrons, and net charge for the difference between protons and electrons.
  3. Check the model: Confirm that the conclusion matches the structure of the atom and the evidence represented by the diagram, notation, or periodic table.

There is one more positive proton than negative electron, so the ion has a positive one charge.

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