Assessment on Atomic Theory

(True or False) Protons and neutrons are particles with mass that are found in the nucleus of an atom. Electrons have very little mass and orbit the nucleus in the electron cloud.

• True

• False

Answer explanation

Explanation: Protons and neutrons are subatomic particles located in the nucleus of an atom, contributing to most of the atom's mass. Electrons, on the other hand, are much lighter and move around the nucleus in regions called electron clouds.

(True or False) Protons have a negative charge, electrons have no charge, and neutrons have a negative charge.

• True

• False

Answer explanation

Answer Explanation: Protons actually have a positive charge, electrons have a negative charge, and neutrons have no charge. Therefore, the statement is false.

(Select all that apply) Which of the following characteristics can be used to distinguish between a proton and an electron?

• Mass
• Location
• Charge
• Color
• Stickiness

(Type in your answer) Fluorine (F) has an atomic number of 9 and an atomic mass of 19. How many protons, neutrons, and electrons does a neutral atom of fluorine have? (use this format for your answer: #, #, #)

Answer explanation

Explanation: A neutral atom of fluorine has 9 protons, as indicated by its atomic number. The number of electrons in a neutral atom is equal to the number of protons, so it also has 9 electrons. The atomic mass is the sum of protons and neutrons, which is 19. Therefore, the number of neutrons is 19 - 9 = 10.

(Type in your answer) Indium (In) has an atomic number of 49 and an atomic mass of 115. How many protons, neutrons, and electrons does a neutral atom of Indium have? (use this format for your answer: #, #, #)

Answer explanation

Explanation: A neutral atom of indium has 49 protons, as indicated by its atomic number. The number of electrons in a neutral atom is equal to the number of protons, so it also has 49 electrons. The atomic mass is the sum of protons and neutrons, which is 115. Therefore, the number of neutrons is 115 - 49 = 66.

Calcium-42 has an atomic mass of 42 and an atomic number of 20. How many neutrons does this isotope of Calcium contain?

• 42

• 62

• 22

• 20

Answer explanation

To find the number of neutrons, subtract the atomic number from the atomic mass: 42 (atomic mass) - 20 (atomic number) = 22 neutrons.

Lithium-6 has an atomic mass of 6 and an atomic number of 3. How many neutrons does this isotope of Lithium contain?

• 1
• 2
• 3
• 4

Answer explanation

To find the number of neutrons, subtract the atomic number from the atomic mass: 6 (atomic mass) - 3 (atomic number) = 3 neutrons.

(Select all that apply) Which of the following are subatomic particles that comprise an atom?

• Neutron
• Electron
• Proton
• Quarkling
• Fluxion

Answer explanation

Fluxion and Quarklings while based on real sub-subatomic particles they are not themselves subatomic particles.

(Type in your answer) What is the name of the element with an atomic number of 51, the atomic mass (rounded to the nearest whole number), and its atomic symbol? (separate your answers with commas)

Answer explanation

**Explanation:** The element with atomic number 51 is Antimony. Its atomic mass is approximately 121.760, which rounds to 122. The atomic symbol for Antimony is Sb.

(Type in your answer) What is the name of the element with an atomic number of 14, the atomic mass (rounded to the nearest whole number), and its atomic symbol?

Answer explanation

**Explanation:** The element with atomic number 14 is Silicon. Its atomic mass is approximately 28.0855, which rounds to 28. The atomic symbol for Silicon is Si.