Atomic Theory & Structure

Front

What is the nucleus of an atom?

Back

The nucleus is a tiny but very dense, positively charged portion of the atom that holds most of the atomic mass.

Front

Who discovered the electron?

Back

J.J. Thomson discovered the electron within the atom.

Front

How did each model of the atom contribute to atomic theory?

Back

Each model built upon the other to show new particles or properties of previously discovered particles.

Front

Who proposed the Atomos Theory?

Back

Democritus was the first person to propose a theory about an atom called the Atomos Theory.

Front

What did Bohr's model of the atom state?

Back

In Bohr's model, electrons move in definite orbits around the nucleus.

Front

What is atomic theory?

Back

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

Front

What are electron shells?

Back

Electron shells are the regions around the nucleus where electrons are likely to be found.

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.

Front

What is the charge of a proton?

Back

A proton has a positive charge.

Front

What is the charge of an electron?

Back

An electron has a negative charge.