Transcript Lesson 1 Introduction to Atoms

Unit: Chemistry
Lesson 1: Introduction to
Atoms
Essential Questions:
1.) How did atomic theory
develop?
2.) What is the modern model
of the atom?
How did atomic theory develop?
The smallest particle
Atom
of an element
Dalton
 Atoms cannot be broken into
smaller pieces
Dalton thought
that atoms were
like bowling balls
that could not be
broken.
Dalton’s Model
.
Thomson
 Atoms are made of smaller parts
Negatively charged particles
in an atom
Electron
 Atoms contain a positive charge
An atom has electrons
scattered throughout it
like seeds in a
watermelon.
Thomson’s Model
Thomson suggested that atoms had negatively charged electrons set
in a positive sphere. Each electron is represented by the symbol e−.
Rutherford
 An atom is mostly empty space with a
positive center
The center of an atom
Nucleus
Positively charged particles
in an atom’s nucleus
Protons
The pit models the nucleus of an
atom and the fruit is the space
with electrons.
Rutherford’s Model
According to Rutherford’s model, an atom was mostly open space. The
“6+” in the model means that there are six protons in the nucleus.
Bohr
 Electrons are found in specific orbits
Cloud Model
 Electrons move within a cloudlike
region