Chemistry - Atoms, molecules and ions

Protons, neutrons and electrons

The plum pudding model and the nuclear model

Ernest Rutherford

Rutherford fired alpha particles at a gold sheet. The plum pudding model would have all of these negatively charged alpha particles bounce off but most flew through and only some bounced back

It showed that atoms are mostly empty space with a small positively charged center

The number of protons and neutrons in an atom or isotope

The number of protons / electrons in an atom

Isotopes are forms of an element that have the same number of protons but a different number of neutrons

An ionic bond is when atoms that need to loose electrons give electrons to atoms that need to gain electrons in order to get a full outer shell

A covalent bond is when two or more atoms share their electrons to get a full outer shell