write about what you know of the following people: john dalton j. j. thomson ernest rutherford

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:

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

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


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?


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)


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


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)


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


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


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


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


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


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


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





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.


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.


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?


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?


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.


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


Nuclear Symbol Superscript indicates the mass number

(p+n) Subscript indicates the atomic number

(p)

Hyphen Notation Element symbol, hyphen, mass number


Mathematical Equations

Atomic number = # of p (also tells you # of e)

Mass number = # of p + # of N

Number of Neutrons = mass # - atomic #


Complete worksheet 2 and 3

Quantum Atomic ModelConcept

Concept: Quantum Atomic Model






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


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


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


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






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


4 types of Atomic Orbitals s, p, d, and f


S-orbital Shaped like a sphere 1 per energy level Can hold 2 electrons S-block is groups 1-2


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


D-orbital Begins at energy level 3 5 different orbitals Each hold 2 electrons for a total of

10 electrons Groups 3-12


F-orbital Begins at 4th energy level 7 different orbitals Each has 2 electrons for a total of 14

electrons


Be looking over notes from board and yesterday’s powerpoint


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


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


10/18/2012

Write the orbital configuration for: Sodium Magnesium


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


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


Valence Electrons

Electrons located in the last energy level

Determines the chemical properties of that element

write about what you know of the following people: john dalton j. j. thomson ernest rutherford

Documents

modern atomic theory

atomic structure bell

daltons atomic theoryfirst

daltons theory

bohrs models of th

atomic structurekey

particles protons

charges of subatomic