14-3 Particles of Matter

Matter The term matter describes all of the physical substances around us: your table, your body, a pencil, water, and so forth

Matter Anything that has mass and takes up space (has volume) Made up of different kinds of atoms

Matter Includes all things that can be seen, tasted, smelled, or touched Does not include heat, sound, or light

All matter is made of atoms, the smallest particle of an element

Models Models are often used for things that are too small or too large to be observed or that are too difficult to be understood easily

Models In the case of atoms, scientists use large models to explain something that is very small Models of the atom were used to explain data or facts that were gathered experimentally. So, these models are also theories

Early Models of the Atom Democritus (440 B.C.) Universe was made of empty space and tiny pieces of stuff Tiny pieces of stuff called “ATOMOS” or “UNCUTTABLE” Atoms could not be divided Atom – still used today!

Basic Model of the Atom Dalton (1802) Atoms can’t be broken into smaller pieces Atoms of the same element are the same An element always has the same properties Atoms of different elements are different Compounds consist of atoms of different elements joined together compounds split into atoms Atoms of each element have a unique mass Masses of elements in a compound are in a set ratio, for example H2O or C6H12O26

Atoms & Molecules Today Elements Combine Compounds smallest piece smallest piece Atoms Combine Molecules Atom: extremely, extremely, extremely small Images seen with a scanning, tunneling microscope Molecule group of atoms joined together by a chemical bond act as a single unit basic particle of a compound