PS 5.1 atomic history

Front

Who proposed the planetary model of the atom?

Back

Neils Bohr proposed the planetary model of the atom, where electrons orbit the nucleus like planets around the sun.

Front

What is the smallest particle of an element that retains its chemical properties?

Back

An atom is the smallest particle of an element that retains the chemical properties of that element.

Front

Who was the first contributor to the atomic theory?

Back

Democritus is considered the first contributor to the atomic theory, proposing that matter is made up of small, indivisible particles called atoms.

Front

List the scientists in order of their contributions to atomic theory from earliest to most recent.

Back

Democritus, John Dalton, J.J. Thomson, Ernest Rutherford, Neils Bohr.

Front

What particle did J.J. Thomson discover in his model of the atom?

Back

J.J. Thomson discovered the electron in his model of the atom.

Front

What is the charge of an electron?

Back

An electron has a negative charge.

Front

What did John Dalton propose about atoms?

Back

John Dalton proposed that all matter is made up of atoms, which are indivisible and indestructible.

Front

What is the nucleus of an atom?

Back

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

Front

What is the charge of a proton?

Back

A proton has a positive charge.

Front

What is an isotope?

Back

An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons.