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Chapter 4 Atomic
Structure
Section 4-1
Objectives
• Describe ancient Greek models of matter
• List the main points of Dalton’s atomic
theory and describe his evidence for the
existence of atoms
• Explain how Thomson and Rutherford used
data from experiments to produce their
atomic models
What is the derivation of the
word “atom” ?
• “a” – not
• “tomos” - cutting
• Matter can only be subdivided
as small as an elemental
particle:___________
Democritus
• About 400 BC
• World is made of 2 things
– 1) -____________
– 2) _____________ called “atoms”
Aristotle
• Matter is continuous
and_______MADE OF ATOMS
• few believers in atoms for nearly
2,000 yrs
• WHY?????????????????
Dalton’s Theory
__________ produced the theory
that all matter is made up of
individual particles called_______,
which cannot be divided.
Main Points to Dalton’s
Theory
• All _______ are composed of atoms
• All atoms of the same element have the
_______ mass, and atoms of different
elements have _______ masses
• _________ contain atoms of more than
one element
• In a particular compound, atoms of
different elements always_________ in
the same way.
Early Research on
Atomic Particles
• Eventually__________were
discovered to Dalton’s Atomic
Theory……..
J.J Thompson
• Created ____________ Experiment
Cathode Ray Studies of the
mid 1800’s
What did these
observations mean?
• Glowing______ in cathode tube was made
of particles
• Particles that composed cathode rays are
negatively charged called__________
• Thomson’s experiments provided the first
evidence that atoms are made of even
smaller _________
Thomson’s Model
•
•
•
•
Called “_____________”
Looks like chocolate chip ice cream
Chocolate is negative particles
Vanilla ice cream is positively charged
matter
Teacher Demo
Investigating Charged Objects
• Pg 102
Rutherford’s Atomic
Theory
• The______________ experiment
Observations
• Most__________particles
passed through the gold foil
• About 1 in 8,000 particles
bounced almost
straight________
Discovery of the Nucleus
• Rutherford’s experiment discovered the
____________
• Nucleus is a dense, positively charged mass
located in the _________ of the atom.
• According to Rutherford’s model, all of an
atom’s_________charge is concentrated
in its nucleus.
Beaker Breaker
1. The gold foil experiment was done
by _________
2. The cathode ray tube experiment
was done by ___________
3. Who discovered the
nucleus?____________
Section 4-2
The structure of an Atom
Objectives
• Identify three subatomic particles
and compare their properties
• Distinguish the atomic number of an
element from the mass number of an
isotope, and use these numbers to
describe the structure of atoms
Definitions
•
Use your book to define the following
2.
Electron-
3.
Neutron-
4.
Atomic number-
5.
Mass Number-
6.
Isotopes-
1.
Proton –
Properties of Subatomic
Particles
• ________, ________, and_______
are subatomic particles
Protons
• A _________is a _________
charged subatomic particle that is
found in the nucleus of an atom
• Each proton is assigned
a_______charge
• Some nuclei contain more than 100
_________
Electrons
• An________ is a___________
charged subatomic particle that is
found in the space outside the
nucleus.
• Each electron has a charge of_____.
Neutrons
• A________ is a________ subatomic
particle that is found in the nucleus of an
atom.
• It has a_______almost exactly equal to
that of a proton
• James_______designed an experiment to
show that neutrons exist.
Comparing Subatomic
Particles
• Protons, electrons, and neutrons can be
distinguished by_______, _______ and_______
in an atom.
• Protons and neutrons have almost the
______mass
• Electrons have a charge that is_________ of the
charge of a proton
• Protons and neutrons are found in the _______,
but electrons are found in the space outside the
nucleus.
Atomic Number
• The_____________ of an element equals
the number of_________ in an atom of
that element
• Atoms of_________elements have
different numbers of protons.
• Atomic number also tells you the number
of _________
• Ex: Sulfur atomic number = _____
• Ex : Carbon (C ) atomic number =_____
Mass Number
• The__________ of an atom is the sum of the
________ and _________in the nucleus of that
atom
• Ex: Aluminum has____protons and_____neutrons
has a mass number of ______
• If you know the atomic number and the mass
number of an atom, you can find the number of
neutrons by_________.
•
Mass number – Atomic number = Number of neutrons
Isotopes
• _________ of an element have the same
_____ number but different _____
numbers because they have different
numbers of _______.
• Ex Oxygen -___ (protons and 8 neutrons)
Oxygen – ___ ( 8 protons and 9 neutrons)
Oxygen -___( 8 protons and 10 neutrons)
Beaker Breaker
• A __________is a neutral subatomic
particle that is found in the nucleus
• An electron has a _________charge
• ______and ________are located in
the nucleus, while_______are
located outside the nucleus
Section 4-3 Modern Atomic Theory
Objectives
• Describe Bohr’s model of the atom and the
evidence for energy levels
• Explain how the electron cloud model
represents the behavior and locations of
electron in atoms
• Distinguish the ground state from excited
states of an atom based on electron
configurations
Bohr’s Model
• Model of atom looks like
a_____________ with planets
revolving around a sun
• Model focused on _________
Bohr’s Model and energy
levels
• The possible energies that electrons in an
atom can have are called____________.
• Energy levels are like _______ on a
staircase, an electron_______exist
between energy levels
• An electron in an atom can move from one
energy level to another when the
atom_____ or ________energy
Evidence for Energy
Levels
• Scientist can measure the energy
gained when electrons ________
energy and move to a _______
energy level.
• They can measure the energy______
when the electron returns to a
________ energy level
Flame Test Lab
• Read page 116 “evidence for energy
levels” in the book
Question :
How do these substances produces
light of different colors?
Electron Cloud Model
• An electron ________ is a visual model of
the most likely_________for electrons in
an atom.
• Scientists use the electron cloud model to
describe the possible locations of
_______ around the __________
• Ex: ________ on a propeller of an airplane
Atomic Orbitals
• An _______ is a region of space around
the nucleus where an electron is likely to
be found
• An electron cloud is a good approximation
of how electrons ________ in their
orbitals.
• Higher energy levels have more than one
________
Modern Atom
1.
Louis de Broglie – proposes that moving
particles like electrons have some properties of
___________.
2.
Erwin Schrodinger develops
mathematical__________ to describe the
motion of electrons in atoms (electron cloud).
3.
James Chadwick- confirms the existence
of_________in the nucleus, which have no
charge
Drawings of Atoms
Electron Configurations
• An electron _________ is the arrangement of
electrons in the orbitals of an atom
• The most stable electron configuration is the one
in which the electrons are in orbitals with
the_________ possible energies
• When all the electrons in an atom have the lowest
possible energies, the atom is said to be in its
_____________.