3rd edition Physical Science Apologia Module 3

Matter cannot be created or destroyed, but it can change forms

_______ developed a theory to explain why elements in a compound always join in the same proportion.

The sum of the protons and neutrons in the nucleus of an atom

A region of space around the nucleus where electrons are most likely to be found

Electrons that are in the highest energy level (the energy level farthest from the nucleus) of an atom of an element

Samples of a pure compound always have the same elements in the same mass proportion

_______ discovered that all matter gives off small negatively charged particles.

Atoms of an element with the same number of protons but different number of neutrons

The rows on the periodic table are called periods.

________ created the currently accepted electron model, the electron cloud model.

Ernest Rutherford discovered both protons and neutrons in the atom.

The number of protons in an atom

________ discovered the nucleus of the atom and created the nuclear model of the atom.