Atoms, Molecules, Matter

Atom

The smallest particle that has the properties of an element.

Molecule

The smallest unit of a substance that shows the properties of that substance.

Objective 1

Describe the structure of matter in terms of atoms and molecules.

    1. Recognize that atoms are too small to see.

    2. Relate atoms to molecules (e.g., atoms combine to make molecules).

    3. Diagram the arrangement of particles in the physical states of matter (i.e., solid, liquid, gas).

    4. Describe the limitations of using models to represent atoms (e.g., distance between particles in atoms cannot be represented to scale in models, the motion of electrons cannot be described in most models).

    5. Investigate and report how our knowledge of the structure of matter has been developed over time.

Structure of Matter

Objectives (the things you need to know and be able to do):

You need to know that:

*Atoms are too small to see.

*Atoms combine to make molecules.

You need to be able to:

*Diagram the arrangement of particles in the physical states (a/k/a phases) of matter (solid, liquid, gas).

*Describe the limitations of models to represent atoms.

*Learn how our knowledge of the structure of matter developed.

Information:

"The scanning tunneling microscope has a small probe which actually more like

"feels" the size of the atoms and reads this out on a computer screen. The

probe can pick up individual atoms. IBM used a STM years ago to spell I B M

with uranium atoms and took a picture of it. But one does not actually

directly "see" the atoms."

Peter Faletra Ph.D.

Assistant Director

Science Education

Office of Science

Department of Energy

All particles of matter are in motion. Particles in solids are closer, and move slower, than a liquid of the same substance. Likewise, particles of liquids and closer, and move slower, than gasses of the same substance.

Atoms are made of a nucleus (protons and neutrons), and electrons that orbit around the nucleus.

If you could take a nucleus of an atom, and enlarge it to the size of a baseball, the closest electron would be out orbiting around near the Rec Center. As you can see, atoms are mostly empty space.