Atoms – The Inside Story

Class NotesTuesday, Sept. 14, 2010

What are atoms?

• Smallest ‘building blocks’ of matter– Matter is anything that has mass and takes up

space• Most mass in an atom is contained in the

middle, called the nucleus• Atoms are composed of 3 different parts:– Protons (+)– Neutrons (0)– Electrons (-)

Where are these particles found in the atom?

• Different theories and atomic models have been tested by many scientists over hundreds of years, but we now think:– Protons are found in the nucleus– Neutrons are found in the nucleus– Electrons are probably found moving around in an

area surrounding the nucleus, called the electron cloud

Atom Concept Map

Particles that make up

atoms

Proton

Positive

Neutron

Neutral

Electron

Negative