Front

What is an atom?

Back

The smallest particle into which an element can be divided and still be the same substance.

Front

What does the atomic number represent?

Back

The number of protons in the nucleus of an atom, which defines the element.

Front

Who proposed the 'plum pudding' model of the atom?

Back

J.J. Thomson.

Front

What is the charge of a proton?

Back

Positive.

Front

What is the charge of an electron?

Back

Negative.

Front

What is the charge of a neutron?

Back

Neutral.

Front

What is an isotope?

Back

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Front

What is the mass number of an atom?

Back

The total number of protons and neutrons in the nucleus.

Front

Who developed the planetary model of the atom?

Back

Niels Bohr.

Front

What is the electron configuration of a neutral sodium atom?

Back

1s² 2s² 2p⁶ 3s¹.