History of the Atom

Front

What does the word 'atomos' mean?

Back

It means 'uncuttable' or 'indivisible', referring to the smallest unit of matter.

Front

Who used the term 'atomos' to describe atoms?

Back

Democritus.

Front

What did Rutherford's gold foil experiment show about atoms?

Back

Atoms are mostly empty space, have a small dense nucleus, and the nucleus is positively charged.

Front

What is the charge of a nucleus in an atom?

Back

The nucleus is positively charged.

Front

How many protons does an atom of carbon have?

Back

6 protons.

Front

What is the atomic number of an element?

Back

The number of protons in the nucleus of an atom.

Front

Can an atom of Helium have 3 electrons?

Back

Yes, because it can be an ion.

Front

What is an ion?

Back

An ion is an atom that has gained or lost electrons, resulting in a charge.

Front

How many electrons does a neutral magnesium atom have?

Back

12 electrons.

Front

What is the relationship between protons and electrons in a neutral atom?

Back

In a neutral atom, the number of protons equals the number of electrons.