Particles of Matter EQ: How do I describe the smallest particles of an element?

Atoms The smallest particle of an element EQ: How do I describe the smallest particles of an element?

Democritus A Greek First to suggest that matter could be divided into pieces and that there is a time when they cannot be cut any further Called the smallest pieces atomos which is Greek for “uncuttable” EQ: How do I describe the smallest particles of an element?

Dalton A teacher from 1802 Proposed the atomic theory His theory has five components EQ: How do I describe the smallest particles of an element?

Dalton’s Ideas Atoms can’t be broken into smaller pieces. –He imagined them as tiny marbles, impossible to break In any element, all atoms are exactly alike. An element always has the same properties EQ: How do I describe the smallest particles of an element?

Dalton’s Ideas Atoms of two or more elements can combine to form a compound Atoms of each element have a unique mass – still have not been able to measure the mass of individual atoms EQ: How do I describe the smallest particles of an element?

Dalton’s ideas The masses of the elements in a compound are always in constant ratio EQ: How do I describe the smallest particles of an element?

Atoms and Molecules Today Molecule – a group of atoms that are joined together act like a single unit Chemical bond – the force that holds two atoms together EQ: How do I describe the smallest particles of an element?

How small are atoms? One sheet of paper is 10,000 atoms thick So small only a scanning tunneling microscope can capture the image a device that "feels" the cloud of electrons that form the outer surface of atoms, rather as a phonograph needle feels the grooves in a record. EQ: How do I describe the smallest particles of an element?

Particle Model The way we explain matter in terms of atoms and molecules EQ: How do I describe the smallest particles of an element?

Class Work and Homework Fill In –What did I learn –Confused –Say –Read Particles of Matter in the folder –Answer questions 1 – 5, p. K 33 EQ: How do I describe the smallest particles of an element?