Quiz on Atomic Structure

Who was the first scientist to theorize that atoms are small bits of matter that cannot be cut into smaller parts?

• J.J. Thomson

• Ernest Rutherford

• Democritus

• Niels Bohr

Answer explanation

Democritus was the first to propose that matter is composed of indivisible particles called atoms, which cannot be divided further. This foundational idea laid the groundwork for modern atomic theory.

What did John Dalton find about atoms?

• Atoms can be divided into smaller parts.

• Atoms of the same element are exactly alike.

• Atoms of different elements are the same.

• Chemical reactions change atoms.

Answer explanation

John Dalton proposed that atoms of the same element are identical in mass and properties, which means they are exactly alike. This foundational idea helped distinguish elements from one another.

What did J.J. Thomson discover about atoms?

• Atoms have a nucleus.

• Atoms have negatively charged particles called electrons.

• Atoms have positively charged particles called protons.

• Atoms have no charge.

Answer explanation

J.J. Thomson discovered that atoms contain negatively charged particles called electrons, which was a groundbreaking finding that changed the understanding of atomic structure.

What did Ernest Rutherford discover about atoms?

• Atoms have a nucleus with positively charged particles called protons.

• Atoms have no nucleus.

• Atoms have negatively charged particles called electrons.

• Atoms are indivisible.

Answer explanation

Ernest Rutherford discovered that atoms have a nucleus containing positively charged particles called protons, which was a significant advancement in understanding atomic structure.

What did Niels Bohr suggest about electrons?

• Electrons are stationary.

• Electrons orbit the nucleus in paths like a planet orbits the sun.

• Electrons are inside the nucleus.

• Electrons have no charge.

Answer explanation

Niels Bohr proposed that electrons move in specific orbits around the nucleus, similar to how planets orbit the sun. This model contrasts with the idea of stationary electrons or those located within the nucleus.

What did the Cloud model find about electrons?

• Electrons orbit the nucleus in fixed paths.

• Electrons move rapidly in a cloudlike area.

• Electrons are stationary.

• Electrons are inside the nucleus.

Answer explanation

The Cloud model describes electrons as moving rapidly in a cloudlike area around the nucleus, rather than following fixed paths or being stationary. This reflects the probabilistic nature of electron positions.

Who discovered that the nucleus also contains neutrons?

• J.J. Thomson

• Ernest Rutherford

• James Chadwick

• Niels Bohr

Answer explanation

James Chadwick discovered neutrons in 1932, providing evidence that the nucleus contains not only protons but also neutrons, which are neutral particles. This discovery was crucial for understanding atomic structure.

What charge do protons have?

• Negative

• Positive

• Neutral

• No charge

Answer explanation

Protons have a positive charge, which is fundamental to their role in atomic structure. This positive charge balances the negative charge of electrons, allowing atoms to maintain stability.

What charge do neutrons have?

• Negative

• Positive

• Neutral

• No charge

Answer explanation

Neutrons are subatomic particles found in the nucleus of an atom and have no electric charge. Therefore, the correct answer is 'Neutral', indicating that they do not carry a positive or negative charge.

What charge do electrons have?

• Negative

• Positive

• Neutral

• No charge

Answer explanation

Electrons carry a negative charge, which is fundamental to their role in electricity and chemistry. This distinguishes them from protons, which have a positive charge, and neutrons, which are neutral.