Atomic Theory History Unit 02 Flashcard

Front

What was Niels Bohr's contribution to atomic theory?

Back

Electrons move around a nucleus in prescribed orbits.

Front

In what year did Henry Moseley publish his paper on atomic number?

Back

1914.

Front

True or False: All matter is made up of atoms.

Back

True.

Front

Who determined that all atoms are mostly empty space with mass concentrated at the nucleus?

Back

Ernest Rutherford.

Front

Which ancient Greek philosopher first proposed the idea of atoms?

Back

Democritus.

Front

What is the atomic theory?

Back

A scientific theory that matter is composed of discrete units called atoms.

Front

What did John Dalton contribute to atomic theory?

Back

He proposed that all matter is made of indivisible atoms and that atoms of the same element are identical.

Front

What is the significance of the atomic number?

Back

The atomic number is the number of protons in the nucleus of an atom, determining the element's identity.

Front

What did Ernest Rutherford's gold foil experiment demonstrate?

Back

It demonstrated that atoms are mostly empty space with a dense nucleus.

Front

What is the difference between an atom and a molecule?

Back

An atom is the smallest unit of an element, while a molecule is a group of two or more atoms bonded together.