History of The Atoms

(Sapling) Which of the ideas of earlier scientists are NOT part of the modern atomic theory?

1. Atoms are made of a diffuse, positively charged mass and electrons are scattered throughout the mass, like plums mixed in a pudding. 2. Atoms cannot be divided into smaller particles.

(Sapling) Democritus believed...

1. Atoms cannot be created or destroyed 2. Matter is composed of very small particles called atomos (atoms) 3. Atoms can't be split into smaller parts.

(Sapling) What statements were parts of Dalton's original atomic theory?

1. Matter is comprised of small particles called atoms 2. Atoms of the same element have the same size, mass, and structure 3. Atoms cannot be created or destroyed in a chemical reactiom 4. Different elements have atoms of different masses and properties.

(Sapling) Ernest Rutherord was a prominent scientist who contributed to the research of the atomic structure. Which are true?

1. Rutherford disproved the plum pudding model of the atom. 2. Rutherford theorized that atoms contain a positively charged region and called this region the atomic nucleus.

(Sapling) Aristotle believed...

1. matter is composed of earth, air, fire, and water 2. empty space does not exist.

(Millikan) What year did he make his discovery?

1909

(Ernest Rutherford) What year did he make his discovery?

1911

(Niels Bohr) What year did he make his discovery?

1913

(Schrodinger) What year did he make his discovery?

1926

(James Chadwick) What year did he make his discovery?

1932

(JJ Thomson) What year did he discover the electron?

1987

(Sapling) Which statement could Democritus and Aristotle agree on?

All matter is made up of basic components

(Sapling) In 1909 Ernest Rutherford designed an expirement in which he shot alpha particles at gold foil. What would Rutherford have observed if the "plum pudding" model of the atom was correct?

Although most alpha particles would pass through the foil, some would be deflected at small angles due to the positive charge.

(Modern Atomic Theory) Define an isotope?

Are atoms of the SAME elements that differ in the number of neutrons

2nd scientist (300 B.C) Believer

Aristotle

(DEMOCRITUS) Believed that matter was composed of tiny indivisible particles called _______ (atoms)

Atomos

(John Dalton) All matter is composed of extremely small particles called __________.

Atoms

(John Dalton) __________ cannot be subdivided, created, or destroyed.

Atoms

(Modern Atomic Theory) What is the average atomic mass. Ex. Carbon-14

Average of all naturally occurring isotopes of that element.

(Modern Atomic Theory) States that atoms of an element have a characteristic _______________ ________ which is unique to that element.

Average, mass

(ARISTOTLE) Believed that all matter is made of _________ components.

Basic

John Dalton

Believed all matter is composed of atoms. (Agree w/ Democritus) Believed atoms of a given & different element are identical & different through size, mass, & other properties. Believed atoms cannot be subdivided, created, or destroyed. (Agree w/ Democritus) Believed atoms of different elements combine to form compounds through simple whole number ratios. Believed in chemical reactions atoms are combined, separated, or rearranged.

Aristotle

Believed that matter is composed of earth, air, fire, and water. Believed that empty space does NOT exist Believed that all matter is made up of basic components.

Democritus

Believed that matter was composed of tiny indivisble particles called atomos. & that all matter is made of basic componets that CAN'T create, destroy, or split into smaller parts. Experiment: none

(Niels Bohr) What was his atomic model called?

Bohr atomic model

Ernest Rutherford...

Carried out experiments that measured the scattering of alpha particles by heavy atoms. AND proposed the plnetary model of the atom with most of the mass of the atom concentrated in a very small nucleus.

(Millikan) What did Roger Millikan discover?

Charge & mass of an electron

(Conclusions from the Study of the Electron) All elements must contain identically ___________ ______________.

Charged, electrons

(Niels Bohr) What experiment did he perform?

Collided hydrogen into hydrogen

(John Dalton) In chemical reactions, atoms are __________, __________, or ___________.

Combined, separated, or rearranged.

(DEMOCRITUS) Believed that all matter is made up of basic components (atoms) that can't be __________,______________, or ________ into smaller parts.

Create, destroy, or split

1st scientist (400 B.C) Believer

Democritus

(James Chadwick) What theory or discovery did he make?

Discovered neutrons.

(JJ Thomson) What is a negatively charged particle called?

Electron

(JJ Thomson) What theory or discover did he make?

Electron

(Sapling) Which was NOT apart of Bohr's atomic model?

Electron's movement is more complex than a simple orbit.

(Schrodinger) What theory or discovery did he make?

Electrons move like waves

(JJ Thomson) Why was Thomson's atomic model called the "plum pudding" model?

Electrons were like plums embedded in a positively charged "pudding"

(Niels Bohr) What theory or discovery did he make?

Electrons were orbited around the nucleus, on energy levels or shells.

(ARISTOTLE) Believed that _____________ space does not exist.

Empty

6th scientist (Nucleus + Protons)

Ernest Rutherford

James Chadwick

Experiment: Bombarding beryllium with alpha particles. Discovery: Neutrons Year: 1932

JJ Thomson

Experiment: Cathode rays to discover negatively charged particles. Discovery: Electron Year: 1897 Atomic Model name: Plum Pudding

Niels Bohr

Experiment: Collided hydrogen into hydrogen Theory: Electrons were orbited around the nucleus, on energy levels or shells. Year: 1913 Atomic Model Name: Bohr atomic model

Ernest Rutherford

Experiment: Gold Foil Discovery: Nucleus (1911), Protons (1918) Year: 1911 Atomic Model Name: Rutherford Model

Schrodinger

Experiment: Mathematical equations to describe the likelihood of finding an electron in a certain position. Discovery: Electrons move like waves Year: 1926 Atomic Model Name: Quantum Mechanical

Robert Andrews Millikan

Experiment: Oil drop apparatus Discovery: Charge + mass of electron Year: 1909 Atomic Model Name: Oil-drop Apparatus

(DEMOCRITUS) He has no ____________ evidence to support his thoughts.

Expiremental

(Ernest Rutherford) What experiment did he perform and how did it work?

Gold Foil experiment- Alpha particles fired at gold foil. Particle hits on the detecting screen.

(James Chadwick) What experiment did he perform?

He discovered neutrons by bombarding beryllium with alpha particles.

(Sapling) In his discovery of the nuclear atom, what experiment did Rutherford design?

He shot alpha particles at metal foil

(Schrodinger) What experiment did he perform?

He used mathematical equations to describe the likelihood of finding an electron in a certain position.

(sapling) Which describes a shortcoming of Bohr's nuclear atom model?

IT could not pedict enerfy levels for atoms with more than one electron.

(Sapling) In the 1890's.....Scientist who discovered that cathode rays consist of steam of electrons.....

J.J Thomson

4th scientist (Electron)

J.J Thomson

3rd Scientist (1808) Believer

JOhn Dalton

9th scientist (last) Neutrons

James Chadwick

(Sapling) In 1909 Ernest Rutherford designed an experiment in which he shot alpha particles at gold foil. What did he actually observe during his experiment?

Most of the alpha particles went straight through the foil undeflected, and a few bounced.

(Ernest Rutherford) How did the particles behave during Rutherford's experiment?

Most particles pass through, but few deflected.

7th scientist ( Electron's orbit )

Niels Bohr

(Ernest Rutherford) What theory or discovery did he make?

Nucleus

(Millikan) What experiment did he perform?

Oil drop apparatus

(Millikan) What was his atomic model called?

Oil- Drop Apparatus

(Modern Atomic Theory) Atoms cannot be subdivided, created, or destroyed in ____________ ______________ ____________. However, these changes CAN occur in nuclear reactions.

Ordinary chemical reactions

(Conclusions from the study of the electron) What accounts for the mass of the atom?

Other particles/protons/ neutrons

Dmitir Menedeleev discovered..

Periodic changed in properties of elements when they are listed in order of their atomic weights.

(JJ Thomson) What was his atomic model called?

Plum Pudding

(Conclusions from the study of the electron) How can atoms be neutral?

Positive particles in the atom to balance the negative electron.

(Ernest Rutherford) In 1918 what other discovery did he make?

Protons

(Schrodinger) What was his atomic model called?

Quantum Mecanical

5th scientist ( Charge + mass of an electron)

Robert Andrews Milikan

(Ernest Rutherford) What was his atomic model called?

Rutherford Model

8th scientist ( Electrons move like waves )

Schrodinger

(John Dalton) How do atoms of different elements combine to form chemical compounds?

Simple whole number ratios

(John Dalton) How do atoms of different elements differ?

Size, made, & other properties

(John Dalton) How are atoms of a given element identical?

Size, mass, & other properties

(DEMOCRITUS) A Greek philosopher was the first person to ________ about atom's existence.

Think

(JJ Thomson) What experiment did he perform?

Used cathode rays to discover negatively charged particles.

(ARISTOTLE) A Greek philosopher who believed that matter is composed of ___________, _____, ________, and __________.

earth, air, fire, and water

J.J. Thomson discovered..

electrons

J.J Thomson..

experimented with the deflection of cathode rays

(Niels Bohr) Electrons in each orbit have a ________ amount of energy

fixed

(Niels Bohr) Electrons move to ____________ orbitals when they ______________ energy.

higher, recieve

(Niels Bohr) Electrons return to a __________ energy orbit when they ______________ energy.

lower, release

Niels Bohr...

model of the hydrogen atom led to an accurate calculation of the wave lengths of light emitted by an excited hydrogen atom. AND modified the planetary model of the atom by suggesting electrons could travel about the nucleus in only a few discrete stable orbits.

(Niels Bohr) His model though could only predict energy levels for atoms with ___________ electron- Just hydrogen.

one

(Ernest Rutherford) Based off of Rutherford's findings we can conclude that the nucleus of the atom is ____________,___________________, ___________________________________.

small, dense, positively charged