Chemistry Day 6 Friday, September 13th – Monday,

September 16th, 2019 See last week’s powerpoint for these notes

Chemistry Day 7 Tuesday, September 17th – Wednesday,

September 18th, 2019

Do-Now Title: “Inquiry Demo” 1.  Write down today’s FLT 2.  What do you think atoms are? 3.  What do you think atoms are made of? 4.  Draw what you think an atom looks like. Label

your drawing. 5.  What tools do you think you would need in order

to discover or study atoms? 6.  Underneath your do-now, write “Demonstration

Notes”

Finished? Take out your planner and table of contents.

Demo •  Therewillbeasponge,rubbingalcohol,dryice,andasealedglassjar

•  Underneathyourdo-now,writeapredictionaboutwhatyouTHINKwillhappen

•  Useyourpro-talksentenceframe“Inmyopinion…because…”tomakeapredictionaboutwhatyouTHINKwillhappen.

Demonstration • Wealreadypredictedwhatwewillsee

Observationexpectations:– Watchwithyoureyes– Waituntilthedemonstrationisfinishedtowriteorsayanything

– Summarizein1-2sentencesORasimplediagram

Demo • Now,writedownthreequestionsyouhaveaboutwhatyousaworabouttheexperimentalvariables.

• Questionsshouldbescience-relatedandsomethingyoucannotyetanswer

Demonstration •  Partner(s):•  Shareeachofyourquestionswitheachother

•  Decideasagroupwhichquestionisthe“best”andcouldbeansweredwithadditionalevidence,andeveryoneshouldwriteitontheirpaper.

•  Ifitisyourownquestion,simplyputastarnexttoit

Explanation •  Now,wewillrewatchthevideowiththeexplanation.

•  Remember–thisisapreviewintowhatwearelearning.Wewillgoovertheseconceptsagain.

• Writedown2-3piecesofevidencethatcouldusetohelpexplaintheexperimentoryourquestion.

Conclude •  Useyourevidencetotrytoansweryourquestion.Youmayneedtomakeaninference.

•  Useoneofthefollowingpro-talksentenceframes:– “Ifwelookatboth….and….Wecanseethat….”

– “Basedontheevidence,suchas…,wecanconcludethat….”

FLT •  I will be able to describe early ideas

about the atom by completing Early Atomic Theory Notes A

Standard HS-PS1-8:Developmodelstoillustratethechangesinthecompositionofthenucleusoftheatomandtheenergyreleasedduringtheprocessesoffission,fusion,andradioactivedecay

Notes Protocol • Title your notes & add assignment # • Complete Cornell-style • Copy down all bolded ideas • Noise level 0 • Raise hand to question/comment • Be prepared to pair-share-respond

Early Atomic Theory: Part A

What is an Atom?

What is an Atom? •  Atom=thesmallestparticleofanelementthatretainsitsidentityinachemicalreaction

•  Anatomisextremelysmall-whatwouldbeneededinorderforpeopletodiscoverit?

A history of the atom

•  AncientGreece:PhilosopherDemocritusdidnotdiscovertheatom,buthewasoneofthefirsttosuggesttheirexistence.

A history of the atom •  Democritusdescribedatomsasindivisibleandindestructible.

•  Washecorrect?Couldhesupporthisideas?

•  àTherewasnoevidencetosupportDemocritus’ideas(yet)

John Dalton - 1776-1844 •  JohnDaltonwasachemistwhostudiedgases,pressure,andtheexistenceofatoms.

John Dalton - 1776-1844 •  JohnDalton=supportedDemocritus’ideawithscientificevidence.

•  Cameupwiththeearlyideasforatomictheory...

Dalton’s Atomic Theory 1.  All elements are composed of tiny

indivisible particles called atoms

Dalton’s Atomic Theory 2.  Atoms of the same element are identical.

The atoms of any one element are different from those of any other element.

Dalton’s Atomic Theory 3.  Atoms of different elements can mix or

combine in simple whole-number ratios to form compounds

Dalton’s Atomic Theory 4.  Chemical reactions occur when atoms are

separated, joined, or rearranged. Atoms of one element, however, are never changed into atoms of another element as a result of a chemical reaction.

Dalton’s Atomic Theory Note:Not all of Dalton’s ideas were correct...as we will see when we talk about modern atomic theory :)

How Can We Study Atoms? •  Atomscanbeseenusingextremelyhighpoweredmicroscopes,suchasscanningtunnelingmicroscopes.

Sample Questions 1. The ancient Greek philosopher credited with suggesting all matter is made of indivisible atoms is A. Plato B. Aristotle C. Democritus D. Socrates

Sample Questions 2.  Dalton’s atomic theory improved earlier atomic

theory by a.  teaching that all matter is composed of tiny

particles called atoms b.  theorizing that all atoms of the same element are

identical c.  using experimental methods to establish scientific

theory d.  Not relating atoms to chemical change

Sample Questions 3.  Individual atoms are observable with a.  the naked eye b.  a magnifying glass c.  a light microscope d.  a scanning tunneling microscope

Pair-Share-Respond 1. Whatisanatom?2. WhatdidDemocritusbelieve?3. ListthefourpartsofDalton’satomictheory.

Chemistry Day 8 Thursday, September 19th – Friday,

September 20th, 2019

Do-Now Title: “BrainPOP: Atoms” 1.  Use your periodic table to complete the do-

now (questions 1-10) on the worksheet provided. Do not turn over until instructed to do so.

Finished? Take out your planner and table of

contents.

BrainPOP:Atoms

• WatchtheBrainPOPvideo• Wewillcompleteashortactivityinourgroupsafterwards

https://www.brainpop.com/science/matterandchemistry/atoms/

FLT •  I will be able to describe early atomic

models by completing Early Atomic Theory Notes B

Standard HS-PS1-8:Developmodelstoillustratethechangesinthecompositionofthenucleusoftheatomandtheenergyreleasedduringtheprocessesoffission,fusion,andradioactivedecay

Structure of the Atom

What is an atom made of? •  As it turns out, atoms ARE divisible, as three

main subatomic particles were discovered: §  Protons

§  Abbreviation: p+

§  Neutrons §  Abbreviation: n0

§  Electrons §  Abbreviation: e-

Subatomic Particles •  Protons = •  Charge: +1 charge •  Location: particles found in the nucleus of an

atom •  Mass: Relative mass = 1

Subatomic Particles •  Neutrons = •  Charge: uncharged •  Location: particles found in the nucleus of an

atom •  Mass: Relative mass = 1

Subatomic Particles •  Electrons = •  Charge: -1 charge •  Location: particles found orbiting around the

nucleus •  Mass: Insignificant mass

How???? •  If atoms were so difficult to discover given their

tiny size, how were subatomic particles discovered??

What does this mean? •  What do we know about the two ends of

magnets? •  What happens when we push magnets close

together (two different things can happen)? Why?

The discovery of the electron... •  In 1897, J.J. Thomson discovered the electron •  He conducted experiments using electric currents

passing through gases at low pressure

The discovery of the electron... •  These electric currents produced a cathode

ray (a glowing beam) that traveled from the cathode (-) to the anode (+)

What does this look like?

In summary •  Because the movement of the stream was from

the cathode (negative end) to the anode (positive end), there must be some part of the atom that is NEGATIVELY charged

Protons & Neutrons •  1886: Goldstein performed a similar experiment

and observed that there were positively-charged particles traveling toward the cathode. These positive particles would later be called protons.

Protons & Neutrons •  1932: Chadwick

discovered the neutron. This particle was hard to discover because it is neutral, but it has a significant mass (about equal to a proton) that Chadwick studied.

Our Particles

Okay, so there are three particles... •  How did scientists figure out the atom’s

composition?

Developing Atomic Theory… •  Dalton thought atoms were

simply indivisible spheres •  plum pudding model: J. J.

Thomson thought there were just (-)-charged particles scattered within a (+)-charged sphere

•  But then someone else discovered the nucleus...

Ernest Rutherford •  In 1911, Rutherford’s

experiments involved shooting a beam of POSITIVELY CHARGED alpha particles at a thin sheet of gold foil

•  He noticed that the vast majority of alpha particles passed through the foil easily.

•  However, there were a FEW particles that were DEFLECTED back (did not go through).

•  Theonesthathitdeadcenterwerecompletelyreflected

Rutherford’s Conclusions •  Most of the particles passed

through --> Most of an atom is empty space

•  A few (very few) particles were deflected back --> since the alpha particles are positive, there must be a tiny, dense, positively-charged center in an atom

Our atomic model so far... •  Atoms are composed of three main subatomic

particles: p+, n0, e- •  Protons and neutrons are located in the

nucleus of the atom, which is a very small, but dense (contains a LOT of mass in a small volume)

•  Electrons are VERY tiny, negatively charged, and orbit around the nucleus. They make up most of the VOLUME of the atom. – Electronsdeterminethepropertiesofouratoms

But of course... •  ...we still haven’t talked about modern atomic

theory and models yet :)

Sample Questions 1.  Which of the following is NOT an example of a

subatomic particle? a.  proton b.  molecule c.  electron d.  neutron

Sample Questions 2.  The nucleus of an atom consists of a.  electrons only b.  protons only c.  protons and neutrons d.  protons and electrons

Sample Questions 3.  Most of the volume of the atom is occupied by

the a.  electrons b.  protons c.  protons and neutrons d.  neutrons

Sample Questions 4.  Which scientist discovered the neutron? a.  Chadwick b.  Dalton c.  Thomson d.  Rutherford

Pair-Share-Respond 1. Identifyourthreesubatomicparticles–listtheircharge,mass,andlocation.

2. DescribeThomson’splumpuddingmodel

3. ExplainwhatwasmissingfromThomson’splumpuddingmodel

4. WhatwereRutherford’stwoconclusions?