Exploring Atomic Structure and Trends

Front

What are the three main subatomic particles found in an atom?

Back

Protons, neutrons, and electrons

Answer explanation

The three main subatomic particles in an atom are protons, neutrons, and electrons. Protons are positively charged, neutrons are neutral, and electrons are negatively charged, making the first answer choice correct.

Front

Which of the following best describes isotopes?

Back

Atoms with the same number of protons but different numbers of neutrons

Answer explanation

Isotopes are defined as atoms that have the same number of protons (which determines the element) but different numbers of neutrons, leading to different atomic masses. Thus, the correct choice is atoms with the same number of protons but different numbers of neutrons.

Front

How is the average atomic mass of an element calculated?

Back

By averaging the masses of isotopes weighted by their natural abundance

Answer explanation

The average atomic mass is calculated by averaging the masses of isotopes, taking into account their natural abundances. This method provides a more accurate representation of the element's mass in nature.

Front

What type of ion is formed when an atom loses electrons?

Back

Cation

Answer explanation

When an atom loses electrons, it becomes positively charged, forming a cation. Anions are formed when atoms gain electrons, while neutral ions have no charge, and radical ions have unpaired electrons.

Front

Convert 5 kilometers to meters.

Back

5000 meters

Answer explanation

To convert kilometers to meters, multiply by 1000. Therefore, 5 kilometers equals 5 x 1000 = 5000 meters. The correct answer is 5000 meters.

Front

Which of the following statements best describes the difference between accuracy and precision?

Back

Accuracy refers to how close measurements are to the true value, while precision refers to how close measurements are to each other.

Answer explanation

The correct choice states that accuracy refers to how close measurements are to the true value, while precision refers to how close measurements are to each other. This distinction is crucial in understanding measurement quality.

Front

Which group of the periodic table contains the noble gases?

Back

Group 18

Answer explanation

The noble gases are found in Group 18 of the periodic table. This group includes elements like helium, neon, and argon, which are known for their lack of reactivity due to having a full valence shell.

Front

What is the electron configuration of a neutral oxygen atom?

Back

Answer explanation

A neutral oxygen atom has 8 electrons. The electron configuration is filled according to the Aufbau principle: 1s^2 2s^2 2p^4, which accounts for all 8 electrons. Thus, the correct answer is 1s^2 2s^2 2p^4.

Front

Which of the following best describes the Bohr model of the atom?

Back

Electrons orbit the nucleus in fixed paths called shells.

Answer explanation

The Bohr model describes electrons as orbiting the nucleus in fixed paths known as shells, which distinguishes it from other models that depict electrons as clouds or scattered throughout a sphere.

Front

What is emitted when an electron in an atom transitions from a higher energy level to a lower energy level?

Back

Photon

Answer explanation

When an electron transitions from a higher to a lower energy level, it releases energy in the form of a photon. This emitted photon corresponds to the difference in energy between the two levels.