unit: chemistry lesson 1: introduction to atoms essential questions: 1.) how did atomic theory...
TRANSCRIPT
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?
Atomos “uncuttable”
The smallest particle Atom
of an element
Dalton
Atoms cannot be broken into smaller pieces
Dalton thought that atoms were like hard balls that could not be broken.
Dalton’s Model.
Thomson Atoms are made of smaller parts
Negatively charged particles Electron
in an atom
Atoms contain a positive charge
An atom has electrons scattered throughout it like seeds in a watermelon.
Thomson’s ModelThomson 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 Protons
in an atom’s nucleus
The pit models the nucleus of an atom and the fruit is the space with electrons.
Rutherford’s ModelAccording 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
The amount of energy Energy level
an electron has
Modern Model of the Atom
Particles in the nucleus Neutron
with no electrical charge
An atom has a nucleus made of positively charged protons and neutral neutrons. The nucleus is surrounded by a cloud of negatively charged electrons.
Modern Model of an AtomA carbon atom has a nucleus made up of positively charged protons and neutral neutrons. The nucleus is surrounded by a cloud of negatively charged electrons.
Particle Charges
Number of protons = number of electrons
Particle Masses
Protons and neutrons make up most of the mass
The number of protons Atomic Number
in the nucleus
Atoms with the same Isotopes
number of protons and
different numbers of
neutrons
The sum of the protons Mass number
and neutrons in the atom
Isotopes of CarbonAll isotopes of carbon contain 6 protons. They differ in the number of neutrons. What is the missing information for each isotope?