Early Ideas
Subatomic Particle Discovery
Isotopes
Subatomic Particles
100

He proposed the idea that matter is made of indivisible particles.

Who is Democritus?

100
He discovered the electron.

Who is J. J. Thompson?

100

It is the subatomic particle that varies within isotopes.

What is the neutron?

100

It is the location of the protons and neutrons in an atom.

What is the nucleus?

200

He believed matter was continuous and not made of atoms and refuted the ideas of Democritus.

Who is Aristotle?

200

The tool used to discover the electron.

What is the cathode ray tube?

200

This nuclear particle does not change depending on the isotope of the element.

What is the proton?

200
It is the negatively-charged particle in an atom.

What is the electron?

300

What Democritus called the small, indivisible particles that vary in size and shape.

What is atomos?

300

What Robert Millikan contributed to atomic theory.

What is the charge of the electron?

300

It is the sum of the protons and neutrons.

What is the mass number?

300
It is the positively-charged particle in an atom.

What is the proton?

400

Earth, Water, Fire, and Air

What is the four elements Aristotle believed all matter was made of?

400

It was discovered with the gold foil experiment.

What is the nucleus?

400
To find this, you must subtract the atomic number from the mass number.

What is the number of neutrons?

400

It is the neutrally-charged particle in an atom.

What is the neutron?

500

He was Democritus's teacher and originally proposed atoms, but not at the robust level that Democritus ultimately did.

Who is Leucippus?

500

The name of J. J. Thompson's model of the atom.

What is the Plum Pudding Model?

500
It is the method by which the mass on the periodic table for an element is calculated.

What is average atomic mass?

500

These are the areas in which electrons can be found.

What are the orbitals?