ATOMS

INTRODUCTION What is the smallest possible piece of an element? If you think of tearing a piece of aluminum foil in half, then tearing the ½’s into quarters, then tear those into eighths, could you continue tearing the pieces into smaller and smaller parts, or would you eventually reach the smallest possible piece of aluminum?

INTRODUCTION

You guessed it. Eventually you would get to the smallest piece of aluminum that still looked and acted like aluminum, in other words that had all the properties of aluminum. At this point you would have an atom of aluminum.

INTRODUCTION Could you then cut that piece into smaller parts, yes, but they would no longer be aluminum. They would not look or act like aluminum.

INTRODUCTION We are going to look at the smaller parts of an atom, and see how they interact with each other.

INTRODUCTION Atomic Structure The atom is made of 3 parts, a proton, a neutron, and an electron. The proton and the neutron are located in the center of the atom in what is called the nucleus. The electrons orbit around the nucleus, kind of like how the moon orbits the Earth.

INTRODUCTION Electrons are tiny, very light particles, they have a negative electrical charge (-), and they move around the outside of the nucleus. Right now it is believed that it is impossible to accurately predict where an electron will be at any specific moment in time.

INTRODUCTION Protons are much larger and heavier than electrons. Protons have a positive charge (+), and are located in the nucleus of the atom. Almost all the mass of the atom is contained in the protons and neutrons, because electrons are so small.

INTRODUCTION Neutrons are large and heavy like protons. They have no electrical charge, and are located in the nucleus of the atom. The number of neutrons in an atom can be the same as the protons or it can vary.

INTRODUCTION

It was once thought that neutrons, protons and electrons were fundamental particles. Fundamental particles can not be broken up into anything smaller. After the invention of the particle accelerator, it was discovered that electrons are fundamental particles, but neutrons and protons are not.

INTRODUCTION These smaller particles are called quarks and leptons. A quark is a tiny particle which makes up protons and neutrons. An electron is a fundamental particle called the lepton.

OBJECTIVES Identify atoms as the smallest particles of an element.

VOCABULARY Proton – positively charged particle. Neutron – neutral particle. Electron – negatively charged particle. Quark – fundamental particle. Lepton – fundamental particle.

VOCABULARY Nucleus – central part of an atom. Fundamental particle – smallest particle from which all other particles can be made.

IN QUESTION When you infer you interpret an observation. Make an inference about this observation: A large white cat ran past me and climbed a fence. 30 seconds later a large black dog ran by me.

NOTES atoms – made of 3 basic parts – proton, (+) charge, larger and heavier than electrons – neutron, (no) charge, larger and heavier than electrons – electron, (-) charge, very small, moves very fast, can’t predict where it is with certainty

NOTES Protons and neutrons are located in the nucleus of the atom. Electrons move about the nucleus in a cloud.

NOTES Quarks and leptons are the smallest fundamental particles we know of. Protons and neutrons are made up of quarks. Electrons are a fundamental particle called a lepton.

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OUT QUESTION If you discovered a new element that was to be added to the periodic table, what would you name it? What would it do?