Atoms

Discovery of the Atom

100

This experiment showed that atoms have a small, dense center called the nucleus.

Gold foil experiment

200

This experiment showed that electrons have a negative charge.

Cathode ray tube experiment

300

This scientist developed the model where electrons move around the nucleus in fixed orbits, like planets around the sun.

Niels Bohr

400

This scientist discovered the electron.

J. J. Thompson

500

This scientist discovered that atoms have a small, dense nucleus at their center.

Ernest Rutherford

Parts of an Atom

100

This subatomic particle has a positive charge and is found in the nucleus of an atom

Proton

200

This subatomic particle has no charge and also resides in the nucleus of an atom

Neutron

300

This negatively charged particle orbits around the nucleus of an atom

Electron

400

This is the central part of an atom, containing protons and neutrons.

Nucleus

500

The number of these in an atom determines what element it is. It also equals the atomic number.

Protons

Elements

100

The arrangement of elements based on increasing atomic number.

The Periodic Table

200

This element has 1 proton and is the lightest element in the periodic table.

Hydrogen

300

This element has 6 protons and is found in all living things.

Carbon

400

This group of elements on the periodic table is known for being nonreactive gases.

Noble Gases

500

This element has the symbol Na and is found in table salt.

Sodium

Isotopes & Ions

100

When an atom has more electrons than protons, it has this type of charge.

Negative

200

When an atom gains or loses electrons, it becomes this.

Ion

300

When an atom loses electrons, it becomes this type of ion.

Positive Ion or Cation

400

These are atoms of the same element that have the same number of protons but a different number of neutrons.

Isotope

500

This is the term for an ion that has a negative charge because it has gained electrons.

Anion