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Bell Work 10/05/2012
Write about what you know of the following people:
John Dalton J. J. Thomson Ernest Rutherford
Unit 2Atomic Structure
Key Learning: The number, type and arrangement of subatomic particles differs with each element.
Basic Atomic ModelConcept
Concept: Basic Atomic Model
CHOOSE 1: HOW TO DO VOCABULARY:
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Write word on front and definition on back of index cards.
Create a poem or rap of vocabulary words and definitions.
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VOCABULARY
Subatomic particles Orbits Nucleus Atom*** Electron cloud Ground state Excited state Absorption emission
Atomic Theory of Matter
John Dalton (1766–1844)
UEQ: What is the structure of the atom?LEQ: What are the locations and charges of subatomic particles?
Dalton’s Atomic Theory First to propose that elements were
comprised of atoms Write 5 parts to Dalton’s Atomic
Theory pg. 68
UEQ: What is the structure of the atom?LEQ: What are the locations and charges of subatomic particles?
Modern Atomic Theory ***modification of Dalton’s Atomic
Theory*** 1. All Matter is composed of atoms 2. Atoms of any one element differ in
properties from atoms of another element
How is this different than Dalton’s Theory? there is no mention of an atom being
smallest particle
J. J. Thomson (1856 – 1940)
Investigated cathode rays.
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
J.J. Thomson Discovered electrons ~1897 by using
cathode ray tubes “plum-pudding” model Thought the atom was solid
Cathode Ray Tubes (mid 1800’s)
Cathode (-) Anode (+) Electric plates (one +, one -)
partially evacuated glass tube that produces a beam between the cathode and anode
Ernest Rutherford (1871 – 1938)
Discovered:Alpha particlesand Beta particles
UEQ: What is the structure of the atom?LEQ: How do Thomson and Bohr’s models of the atom compare?
Ernest Rutherford Credited with the development of the nuclear model for
the atom Used gold foil method. This disproved Thomson’s
model. 3 postulates
Most of atom’s mass and all of its positive charge are in a localized small core---nuclear theory
Most of atom’s volume is empty space in which tiny, negatively charged electrons are dispersed
Since electrons are electrically neutral, there are as many (+) particles (protons) with the nucleus as there are (-) electrons outside the nucleus – or – protons = electrons
UEQ: What is the structure of the atom?LEQ: How do Thomson and Bohr’s models of the atom compare?
10/08/2012 Write Question and Answer
What did Rutherford do that disproved Thomson’s model?
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
Developing a New Atomic Model EM Spectrum Diagram
Energy moves as a wave Includes all electromagnetic radiation Visible light is only a small part of the EM
spectrum (400-700 nm)
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
EM radiation 1.Properties of Light a. visible light
Form of energy traveling in waves b. speed of light (c)
Wavelength X frequency The shorter the wavelength, the greater
the frequency
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
c. Characteristics of Waves Wavelength
Distance from peak to peak of a wave Measured in nm
Frequency Number of waves that pass through a
set point in a given amount of time (waves/sec)
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
Photoelectric effect Emissions of electrons from metals
that have absorbed photons Photon
A particle of EM radiation that has a zero mass and a quantum amount of energy
Quantum Minimum amount of energy that can be
gained or lost by an atom
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
Bohr model Lowest energy state of an atom ground
state An atom having a higher potential energy
excited state Energy must be absorbed to move
electrons to a higher orbit (ground state excited state)
Energy is emitted (given off as EM radiation) when electrons are moved to a lower orbit (excited state ground state)
Bohr’s ideas came from absorption and emission spectra.
When an element is heated up, it gives off light of specific colors:
emission spectrum
When light goes through an element, it
absorbs light of specific colors: absorption spectrum
UEQ: What is the structure of the atom?LEQ: How do Thompson and Bohr’s models of the atom compare?
Bohr model continued… Electrons circle nucleus in orbits
(energy levels) When electrons are in orbit, its energy
is fixed Lowest energy levels are closest to the
nucleus while Highest energy levels are farther away from nucleus
Electrons can move to higher energy levels when hit by a photon
UEQ: What is the structure of the atom?LEQ: What are the locations and charges of subatomic particles?
Structure of the atom3 subatomic particles identify
the element 1. protons
Ernest Rutherford (1909) (+) charge Mass 1.674 X 10 -²7 g – or – 1 amu Relative mass 1.007 276 Held by nuclear forces
UEQ: What is the structure of the atom?LEQ: What are the locations and charges of subatomic particles?
2. Neutron (N) James Chadwick (1932) No charge; neutral Has mass of 1.675 X 10-27 g – or – 1
amu Relative mass = 1.008 665 In nucleus and held by nuclear forces Responsible for isotopes- atoms of
same element with different #’s of neutrons
UEQ: What is the structure of the atom?LEQ: What are the locations and charges of subatomic particles?
3. Electron (e-) J.J. Thomson (1897) ( – ) charge Negligible mass (1/1836 amu –or- 9.11
X10-31g Relative mass 0.000 5486 In orbitals within the electron cloudMakes volume of atom # in last energy level determines the
chemical activity
UEQ: What is the structure of the atom?LEQ: What are the locations and charges of subatomic particles?
Things to Note:
Mass of atom is in the nucleus Atomic radius (Angstrom) is distance
from nucleus to outer edge of electron cloud
Volume of atom is from electron cloud
Periodic Table and atomic structureConcept
Concept: Periodic Table and atomic structure
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Atomic number Average atomic
mass Isotopes Protons Neutrons Electrons Mass number
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
Write question and answer. Write the correct nuclear symbol for
the following:
An atom has 23 protons and 29 neutrons.
An atom has 42 protons and 49 neutrons.
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
You can use information from periodic table to determine the structure of an atom
Atomic number (identifies the element) Atomic symbol Element name Average atomic mass round to nearest
whole number to get the mass # (total number of protons and neutrons that make up nucleus of an isotope.
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
Where does average atomic mass come from?
Average of atomic masses of naturally occurring isotopes of that element
Example: We have a box of 2 types of marbles (100 total). If 25% of these marbles have a mass of 2 g and 75% have a mass of 3 g, then what is the average mass of the marbles?
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
APPLY to elements!!! We have 69.15% of Cu-63, with an
atomic mass of 62.929601 amu and 30.85% of Cu-65 with an atomic mass of 64.927794. What is the average atomic mass?
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
You APPLY to elements!!! There is 99.757 % of O-16 with an
atomic mass of 15.994915 amu and .038% of O-17 with an atomic mass of 16.999132 amu and 0.205% of O-18 with an atomic mass of 17.999160 amu. Calculate the average atomic mass.
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
Isotopes They have the same number of
protons and electrons as a neutral element; but, different number of neutrons (therefore different masses).
Even though this affects average atomic mass –or- mass number, is does not significantly alter their chemical behavior
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
Nuclear Symbol Superscript indicates the mass number
(p+n) Subscript indicates the atomic number
(p)
Hyphen Notation Element symbol, hyphen, mass number
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
Mathematical Equations
Atomic number = # of p (also tells you # of e)
Mass number = # of p + # of N
Number of Neutrons = mass # - atomic #
UEQ: What is the structure of the atom?LEQ: What is the relationship between atomic number, atomic mass and subatomic particles?
Complete worksheet 2 and 3
Quantum Atomic ModelConcept
Concept: Quantum Atomic Model
CHOOSE 1: HOW TO DO VOCABULARY:
Write word and definition. Underline and highlight vocabulary word.
Write word on front and definition on back of index cards.
Create a poem or rap of vocabulary words and definitions.
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VOCABULARY
Quantum numbers
UEQ: What is the structure of the atom?LEQ: Why is the Bohr model insufficient to describe the electron configuration of all elements?
With the Bohr model, we can show what energy level the electrons are in. However, the Bohr model does not show where the electron is exactly located or what orbital they are in.
UEQ: What is the structure of the atom?LEQ: What are the characteristics of the four orbitals in the Quantum model of the atom?
Where are electrons located in an atom?
Electron cloud Electrons are located in specific
locations within energy levels. These levels are known as orbital “home”
Atomic orbitals vary in amount of energy, shape and location outside of nucleus
UEQ: What is the structure of the atom?LEQ: What are the characteristics of the four orbitals in the Quantum model of the atom?
Quantum numbers are used to describe the atomic orbitals and the electrons which occupy them
“address” of an electron Quantum Theory-describe proportion
of electrons mathematically
UEQ: What is the structure of the atom?LEQ: What are the characteristics of the four orbitals in the Quantum model of the atom?
4 Quantum Numbers Principle Quantum Number (n)
Energy level of orbital 7 energy levels (7 periods of table)
Angular Momentum Quantum Number (l) Indicates the shape of the orbital
UEQ: What is the structure of the atom?LEQ: What are the characteristics of the four orbitals in the Quantum model of the atom?
Magnetic Quantum Number (m) Indicates the orientation of the orbital
Spin Quantum Number (+ ½ or – ½ ) Electrons are constantly spinning
(clockwise/counter-clockwise)
Energy and electronsConcept
Concept: Energy and Electrons
CHOOSE 1: HOW TO DO VOCABULARY:
Write word and definition. Underline and highlight vocabulary word.
Write word on front and definition on back of index cards.
Create a poem or rap of vocabulary words and definitions.
Create foldable with words and definitions.
VOCABULARY
Orbital notation Electron configuration
notation Noble gas notation Hund’s Rule Aufbau’s Principle Pauli Exclusion
Principle Heisenberg
Uncertainty Principle
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
Pauli Exclusion Principle No two electrons can have the same
4 quantum numbers Atomic orbitals
Electrons are not only located in energy levels; but, they are more specifically located in orbitals
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
4 types of Atomic Orbitals s, p, d, and f
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
S-orbital Shaped like a sphere 1 per energy level Can hold 2 electrons S-block is groups 1-2
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
P orbital Shaped like a dumbbell 3 per energy level One on x-axis, y-axis, and z-axis Each one holds 2 electrons for a total
of 6 electrons Groups 13-18
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
D-orbital Begins at energy level 3 5 different orbitals Each hold 2 electrons for a total of
10 electrons Groups 3-12
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
F-orbital Begins at 4th energy level 7 different orbitals Each has 2 electrons for a total of 14
electrons
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
Be looking over notes from board and yesterday’s powerpoint
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
Aufbau Principle Electrons fill the atomic orbitals in a
very specific way; based on energy An electron will occupy the lowest
energy orbitals first Follow the arrows to fill atomic
orbital
UEQ: What is the structure of the atom?LEQ: What are the three rules that guides electron configuration?
Hund’s Rule Orbitals of equal energy are filled by
one electron before a second electron is added
UEQ: What is the structure of the atom?LEQ: What are the different ways that you can represent the location of electrons in an atom?
Using orbital notation (combining Aufbau and Hund’s)
Use dashes to represent orbitals and arrows to represent electrons
1. Use atomic number to know how many electrons are present
2. Fill in orbitals based on Aufbau’s chart and Hund’s Rule
UEQ: What is the structure of the atom?LEQ: What are the different ways that you can represent the location of electrons in an atom?
10/18/2012
Write the orbital configuration for: Sodium Magnesium
UEQ: What is the structure of the atom?LEQ: What are the different ways that you can represent the location of electrons in an atom?
Electron Configuration Notation Instead of using dashes and arrows,
use coefficients and superscripts
1. use atomic number to know how many electrons are present
2. exponents show number of electrons in each orbital
3. coefficients represent energy level
UEQ: What is the structure of the atom?LEQ: What are the different ways that you can represent the location of electrons in an atom?
Noble Gas Notation Use noble gases to make notation
shorter Noble gas has a full s and p orbital
octet To read: Add the electrons to the
atomic number of the noble gas
UEQ: What is the structure of the atom?LEQ: What are the different ways that you can represent the location of electrons in an atom?
Valence Electrons
Electrons located in the last energy level
Determines the chemical properties of that element
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