Changing Models of the Atom Flashcards

All 6 cards in this deck

What did Dalton's model say an atom was?

A tiny solid sphere that cannot be divided into smaller particles, with all atoms of an element identical.

Which subatomic particle was discovered first, showing that Dalton's 'indivisible atom' was wrong?

The electron.

Name two features of today's model of the atom that were missing from Dalton's model.

Atoms are made of subatomic particles (protons, neutrons, electrons) and have a nucleus.

True or false? Dalton's model included a positively charged nucleus.

False. Dalton's atoms were solid indivisible spheres; the nucleus came later, after subatomic particles were discovered.

True or false? In today's model, all atoms of the same element are identical.

False. Isotopes of an element have different numbers of neutrons, so Dalton's idea was changed.

Which subatomic particle was the last of the three to be discovered?

The neutron.