Changing Models of the Atom Flashcards

All 5 cards in this deck

What did Dalton's model say about whether an atom can be divided?

Atoms are indivisible — not formed of any smaller particles.

Give two differences between Dalton's model of atoms and today's model.

Modern atoms are formed of sub-atomic particles (protons, neutrons, electrons) and have a nucleus.

True or false? In today's model, atoms of the same element can have different numbers of neutrons.

True. Isotopes exist — Dalton had said all atoms of an element are identical.

What was the plum pudding model of the atom?

The model proposed after electrons were discovered: an atom is a ball of positive charge with negative electrons dotted through it.

Why was the plum pudding model replaced by the nuclear model of the atom?

Experiments showed that the positive charge is not spread through the atom: it is concentrated in a tiny nucleus at the centre, which also holds most of the mass.