C1.2 Atomic Structure

Question 1

Atom

Answer 1

The smallest particle of an element that can exist, consisting of a nucleus and electrons.

Question 2

Nucleus

Answer 2

The central part of an atom containing protons and neutrons.

Question 3

Proton

Answer 3

A positively charged particle found in the nucleus of an atom.

Question 4

Neutron

Answer 4

A neutral particle found in the nucleus of an atom.

Question 5

Electron

Answer 5

A negatively charged particle that orbits the nucleus in shells.

Question 6

Atomic Number

Answer 6

The number of protons in the nucleus of an atom, which defines the element.

Question 7

Mass Number

Answer 7

The total number of protons and neutrons in the nucleus of an atom.

Question 8

Isotope

Answer 8

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Question 9

Electron Shell

Answer 9

The region around the nucleus where electrons are found. Electrons occupy energy levels or shells.

Question 10

What is the relative mass of a proton?

Answer 10

1

Question 11

What is the relative mass of an electron?

Answer 11

0 or 0.0005

Question 12

What is the relative mass of a neutron?

Answer 12

1

Question 13

Explain the electron shell rules.

Answer 13

The first shell can have 2, the second and third have 8 each and the fourth can only have 2.

Question 14

Ion

Answer 14

An atom with the same number of neutrons and protons and but with a different number of electrons

Question 15

Isotope

Answer 15

An atom with the same number of protons but with a different number of electrons.

Question 16

Dalton’s Model

Answer 16

Proposed in the early 1800s, Dalton suggested that atoms are indivisible particles, and each element consists of identical atoms. He also proposed that atoms combine in fixed ratios to form compounds.

Question 17

Thomson’s Model

Answer 17

In 1897, J.J. Thomson discovered the electron and proposed the “plum pudding model,” suggesting that atoms are a positively charged sphere with negatively charged electrons embedded within, like raisins in a pudding.

Question 18

Rutherford’s Model

Answer 18

In 1911, Ernest Rutherford conducted the gold foil experiment, leading to the discovery of the nucleus. His model proposed that an atom consists of a small, dense, positively charged nucleus surrounded by electrons in a mostly empty space.

Question 19

Bohr’s Model

Answer 19

Niels Bohr developed his model in 1913, introducing the idea of quantized electron orbits around the nucleus. Electrons occupy specific energy levels, and energy is absorbed or emitted when electrons move between these levels.

Question 20

Gold Foil Experiment

Answer 20

Conducted in 1909 under the supervision of Ernest Rutherford, this experiment involved firing alpha particles at a thin sheet of gold foil. Most particles passed through, but a small fraction were deflected at large angles. This unexpected result led to the conclusion that atoms have a small, dense, positively charged nucleus at their center, surrounded by mostly empty space where electrons are located. The experiment provided crucial evidence for the nuclear model of the atom and fundamentally changed the understanding of atomic structure.

Question 21

Chadwick’s Model

Answer 21

In 1932, James Chadwick discovered the neutron, proposing that it, along with protons, resides in the nucleus. This discovery explained the mass of the atom and led to a better understanding of nuclear stability.

Question 22

Give your answer in the form (n:1).

What is the ratio between the atomic and nucleic radii.

Answer 22

10000:1