Question 1

Which experiment led to the discovery that atoms have a small, dense nucleus?

Accepted Answer

The gold foil experiment

Question 2

According to Dalton’s atomic theory, which statement is correct?

Accepted Answer

Atoms of the same element are identical in mass and properties.

Question 3

Which subatomic particle was discovered using cathode ray tubes?

Accepted Answer

Electron

Question 4

What is the charge and approximate relative mass of a neutron?

Accepted Answer

Charge: $$0$$, Mass: $$1$$

Question 5

Which of the following best explains why atoms are important in chemistry?

Accepted Answer

Atoms are the fundamental building blocks of matter and determine the properties of substances.

Question 6

Which model of the atom was disproved by Rutherford’s gold foil experiment?

Accepted Answer

The plum pudding model

Question 7

If an atom has 11 protons, 12 neutrons, and 11 electrons, what is its atomic number and mass number?

Accepted Answer

Atomic number: $$11$$, Mass number: $$23$$

Question 8

Which property of light allows scientists to study the structure of atoms?

Accepted Answer

Its ability to be absorbed and emitted at specific wavelengths

Question 9

What is the main reason why most alpha particles passed straight through the gold foil in Rutherford’s experiment?

Accepted Answer

The gold atoms are mostly empty space.

Question 10

Which statement about electrons is correct?

Accepted Answer

Electrons are much lighter than protons and neutrons.

Question 11

A neutral atom of carbon has 6 protons. How many electrons does it have?

Accepted Answer

6

Question 12

Which of the following is NOT a postulate of Dalton’s atomic theory?

Accepted Answer

Atoms can be created or destroyed in chemical reactions.

Question 13

Which observation from the gold foil experiment was most surprising to Rutherford?

Accepted Answer

A few alpha particles were deflected at large angles.

Question 14

Which of the following best describes the nucleus of an atom?

Accepted Answer

It contains protons and neutrons.

Question 15

Which equation correctly represents the relationship between the number of protons ($$Z$$), neutrons ($$N$$), and mass number ($$A) of an $$atom?

Accepted Answer

$$A = Z + N$$

Question 16

Which property of an element is determined by the number of protons in its nucleus?

Accepted Answer

Atomic number

Question 17

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 18

Which scientist is credited with the discovery of the electron?

Accepted Answer

J.J. Thomson

Question 19

Why do scientists use light to study the structure of atoms?

Accepted Answer

Because atoms emit and absorb light at specific wavelengths, revealing their structure.

Question 20

Which of the following best explains why the periodic table is organized by atomic number rather than atomic mass?

Accepted Answer

Atomic number determines the chemical properties of an element.

Atoms: Structure, Theory, and Discovery

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