History Scientist in the Development of Atomic Theory

Albert Einstein

(use Planck's model to help explain the photo electric effect. ) photoelectric experiment (1905) proved particle/wave duality of light

Gold Foil Experiment are what?

-shot a beam of positive particles at gold foil -screen behind foil glow when hit -mostly hit screen -1/8000 times it bounced back shot alpha particles at the gold foil some of them passed through and some of them bounced off this led that there was a center/nucleus of the atom.

What was Dalton's Atomic Theory?

1) All matter consists of indivisible particles called atoms 2) Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements 3) Atoms cannot be created or destroyed 4) Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms 5) Atoms of the same element combine in more than one ratio to form two or more compounds 6) The atom is smallest unit of matter that can take part in a chemical reaction

Rutherford's Atom model conclusions

1. The atom contains a small dense center called the nucleus 2. The nucleus contains most of the mass of the atom 3. The nucleus is positively charged 4. The atom is mostly empty space and the electrons move around in this empty space

Empedocles' idea are

4 basic elements Earth, air, fire, and water

What is a negative electrode called?

A cathode

What can deflect the beam in a cathode ray tube?

A magnet

Max Planck discovered what?

Able to calculate black body spectrum perfectly based on an unusual assumption that the vibration energies of atoms quantify

Postulate 1

All matter consists of indivisible particles called atoms

Louis deBroglie proposed that what?

All matter exhibits wave like properties and that wavelength λ=h/mv

Democritus

All matter is made of atoms

What is a positive electrode?

An anode

What was wrong with Dalton's Atomic Theory?

Atoms can be destroyed only by nuclear reactions. There are different kinds of atoms within an element known as isotopes.

Postulate 3

Atoms cannot be created or destroyed

Postulate 4

Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms

Postulate 2

Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements

Postulate 5

Atoms of the same element combine in more than one ratio to form two or more compounds

What happened when a magnet was placed near glass tube?

Bent beam of light

How did J. J. Thomson discovered the electron?

Cathode rays to deflect negative items or attract one items

Marie Curie demonstrated what?

Cathode rays were in fact charged particles by demonstrating their deflection by both electric and magnetic fields

Who created Dalton's starting point for his Atomic Theory?

Democritus

Ernest Rutherford

Discovered the positively charged nucleus (protons) and empty space with few particles

John Dalton

Each type of matter is made of one type of atom

Name for Rutherford Model

Electric Cloud Model

What are the two metal plates called?

Electrodes

Neils Bohr

Electrons are in energy levels around the nucleus

James Chadwick

English/ 1932/ discovered neutron with no charge and actual mass (protons). Modified Rutherford's atomic model

For timeline who was third

Ernest Rutherford

Who invented Gold Foil Experiment?

Ernest Rutherford

Democritus proposed what theory?

Everything made of particles and space (atomos- atoms as in small particles like chop up floor you get floor particles until you can't chop up)

Where are particles found?

Everywhere

What is Rutherford known for?

Father of nuclear age

Max Planck

Found and calculate black body spectrum perfectly: That the vibration energies of atoms quantify

Henri Becquerel

French/ 1896/ discovered radioactivity working with uranium salts wrapped in photo film

What happened when the glass tube was turned on?

Green Light at cathode (Cathode Ray) (-)

Modern Model

Has an electron cloud instead of orbiting electrons

Uncertainty Principle

Heisenberg's theory that the behavior of subatomic particles is uncertain, suggesting that all of the physical laws governing the universe are based in uncertainty.

Who discovered radioactivity?

Henri Becquerel

Dalton's Law (1808)

If two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be rations of small whole numbers.

James Chadwick's theory?

In the nucleus of an atom there is a particle that has the same weight as a proton, but has no charge

What is double slit experiment?

Interference of light

With the help of his assistant, what did Thomson discover in many nonradioactive elements?

Isotopes

What did Dalton's theory become?

It became a theoretical foundation in chemistry.

What was different about Daltons Table of Elements?

It was much smaller and he used pictures instead of the chemical symbols used today.

For timeline who was second

J.J. Thomson

Who does Ernest Rutherford have in common?

J.J. Thomson was his teacher and Bohr was his student.

Who Discovered the electron?

JJ Thomson

For timeline who was first

John Dalton

What showed that it is smaller than an atom?

Light reflection was greater than deflection of H (smallest atom)

What model did J.J. Thomson use for discover electron?

Looks like chocolate chip cookie model

Who coined the term "radioactivity"?

Marie Curie

Who was the first to come up with quantum theory?

Max Planck

J.J. Thomson

Negative particles (electrons) are attached to positive materials

For timeline who was fourth

Neils Bohr

Atomic Number

Number of protons

Atomic Mass

Number of protons and neutrons The average mass of all the isotopes of an element

Subatomic Particle

Particles found within the atom, mainly protons, neutrons, and electrons.

Which two elements did Marie Curie discover?

Polonium and radium

Atoms are positive or negative?

Positive

What hold protons together in the nucleus (even though they are all positively charged)?

Strong Nuclear Force

What is John Dalton known as?

The Father of the Modern Atomic Theory

Explain Rutherford model

The Rutherford model is a model of the atom devised by Ernest Rutherford. The atom is made up of a central charge surrounded by a cloud of orbiting electrons.

Postulate 6

The atom is smallest unit of matter that can take part in a chemical reaction

Thomson invented __________ to determine properties of positively charged particles.

The mass spectograph

James Chadwick discovered what?

The properties and structure of atomic nuclei, specifically the neutron.

What is Cathode Rays?

Travel in straight lines Cast shadows Exert forces on objects & can transfer energy to objects Are deflected by both magnetic & electric fields Are always the same, regardless of the cathode material or the type residual gas in the tube

True or False: The green light was seen no matter what cathode.

True

Which element did Henri Becquerel discover emitted radiation?

Uranium

Albert Einstein use idea from who and what?

Use planck's model and incorporated it into explanation for the photoelectric effect

Louis de Broglie suggestion Wave Particle

Wave nature of electrons and suggested that all matter has wave properties.

What is photoelectric effect?

Wave particle duality of eight comes from photoelectric effect

Who discovered x-rays?

Wilhelm Rontgen, German physicist

aristotle believed in what?

all matter is continuous and composed of varying amounts of air, earth, fire and water

John Dalton called the particle what?

an atom

Where did the green light move to?

anode (+)

Dalton's atomic theory: atoms of the same element what?

are identical, and are different from atoms of any other element

Democritus named particles

atomos

Aristotle did not believe in what?

atoms

Why Empedocles' idea have been continued for many years?

because of Aristotle promotion that idea

Dalton's atomic theory: atoms of different elements

can be mixed together or chemically combined in simple whole number ratios to form compounds (law of definite proportions)

When was Aristotle being challenged?

challenged for 2000 years, until the age of experimentation in the 18th century

he calculated the _____ and ____ of an atom

charge and mass

Thomas Young

diffraction patter proved wave nature of light - in-phase, out-of-phase waves - constructive, destructive interference Light is a wave not a particle. light exhibited diffraction and interference when passed through two adjacent pinholes.

What are X-rays?

electromagnetic rays, which are emitted when matter is bombarded with fast, negatively charged electrons.

Neils bohr discovered

electrons orbit nucleus at fixed interacts "planetary model" and electrons represented as waves and gave rise to quantum models

John Dalton observed that what?

elements combine in simple whole number ratios

atomos means what?

greek for indivisible

Why is it difficult to discover neutron?

it is neutral and you cannot manipulated with it (or play with it)

What did Marie Curie died from?

leukemia

particles are negative because

move toward electric plate

Max Planck made the revolutionary discovery that the energy of vibrating molecules involved in blackbody radiation existed only in

multiples of certain fixed amounts.

Dalton's atomic theory: atoms of one element

never change into atoms of another element

What did Marie Curie's husband have in his arm?

radiation effects

Cathode Rays are particles because

rays bend by magnet

Marie Curie was the first realized that what?

the atom must have charged constituents that could be separated by observing the ionization of monatomic gases such as helium

Dalton's atomic theory elements are composed of what?

tiny indivisible particles called atoms

Marie Curie won what?

two noble prizes in Chemistry and Physics

Light is a what?

wave, not a particle

Louis deBroglie was first to establish what?

wave-particle duality of matter. Comparing wavelength for an electron and a ball