Atomic Theory

Question 1

The Greek who proposed the idea of a fundamental particle that was indivisible

Answer 1

Democritus

460 BC

Question 2

The father of modern chemistry who defined the concept of the element named oxygen and hydrogen and identified the need for the conservation of mass

Answer 2

Antoine Lavoisier

second half of the 1700s

Question 3

In a close system the total mass of the reactants or starting materials must be equal to the mass of the products

Answer 3

The law of conservation of mass

Question 4

Substances combine in precise proportions (e.g. H2O is two atoms of hydrogen and one atom of oxygen)

Answer 4

The Law of Definite portions

Question 5

1 all material is composed of atoms which are indivisible
2 all the atoms of a given the element are alike in mass and all other respects
3 compounds are formed by combinations of two or more different types of atoms
4 A chemical reaction is a rearrangement of atoms

Answer 5

John Daltons Atomic Theory
(1808)
- 4 postulates

Question 6

The Russian chemist who produced the first modern periodic table

Answer 6

Dmitri Mendeleev 
(1860s)

Question 7

A tabular arrangement of the elements according to their atomic mass

Answer 7

Periodic table

Question 8

The mass of all protons and neutrons that make up an element

Answer 8

Atomic weight

Question 9

A German chemist who developed the Bunsen burner, spectroscope, discovered rubidium and caesium, and investigated the emission spectra of elements

Answer 9

Robert Bunsen

1850s

Question 10

Positively charged particle found in the nucleus of an atom

Answer 10

Proton

Question 11

A particle found in the nucleus of an atom that has no charge.

Answer 11

Neutron

Question 12

A negatively charged particle in an atom, which moves in space around the nucleus

Answer 12

Electron

Question 13

The total number of protons in the nucleus of an atom

Answer 13

Atomic number

Question 14

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

Answer 14

Mass number

Question 15

Atoms with the same atomic number but different mass number.(atoms with the same number of protons but a different number of neutrons)

Answer 15

Isotope

Question 16

A New Zealand born scientist whose experiments with gold foil and alpha particles led to the modern idea of the atom: mostly empty space, positively charged nucleus and negative charges on the outside of the nucleus.
He won the Nobel Prize in physics (1908) for his work in nuclear physics. He identified alpha and beta particles and split the atom.

Answer 16

Ernest Rutherford

Early 1900s

Question 17

Stream of particles and/or energy from a radioactive source

Answer 17

Radiation

Question 18

The spontaneous disintegration of unstable of unstable atomic nuclei accompanied by the emission of alpha, beta or gamma particles

Answer 18

Radioactivity

Question 19

The first woman to win two Nobel prizes in two different categories of science. Awarded for her work in radioactivity.

Answer 19

Marie Curie

Early 1900s

Question 20

Two neutrons and two protons emitted when an unstable nucleus decays.

Answer 20

Alpha particle

Question 21

An electron that is emitted when an unstable nucleus decays

Answer 21

Beta particle

Question 22

A high frequency region of the electromagnetic spectrum emitted when a stable nucleus decays

Answer 22

Gamma radiation

Question 23

A reaction that is self-sustaining as a result of one step starting another step

Answer 23

Chain reaction

Question 24

The time taken for half of an isotope to decay

Answer 24

Half life

Question 25

The splitting of a nucleus into smaller nuclei

Answer 25

Nuclear fission

Question 26

The branch of medicine that uses radioactive isotopes to diagnose, manage and treat diseases

Answer 26

Nuclear medicine

Question 27

The treatment of cancer by radiation

Answer 27

Radiotherapy

Question 28

The fundamental particle of matter made up of protons neutrons electrons

Answer 28

Atom