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Atomic Structure Notes

IQ: The results of which experiment indicated that the nucleus is small and positively charged?a. Thomson’s Cathode Ray tube b.Rutherford’s Gold foil

experimentc. Dalton’s atomic bonding

Atomic Structure:Matter

Anything that has mass and occupies space. All matter is made up of atoms.

What is an atom?• An atom is the smallest

particle of matter.• An atom consists of a very

small, positive nucleus surrounded by one or more e-s.

• EVERYTHING is made of atoms.

The Nucleus• The nucleus is where the

protons and neutrons are located.

• Overall positively charged.

• Held together by a Strong force

• It accounts for 99.9% of the atom’s mass.

• Small and dense• “marble in stadium” –

volume

Subatomic particles:1. What is a proton?

• A positively charged particle (+)• Weighs 1 AMU (atomic mass unit)• Located in the nucleus• Equal to atomic # of an element.• # determines which element the atom

belongs to.

2. What is a neutron?• A neutral particle (no charge)• 1 AMU (atomic mass unit) as heavy as a

proton• Located in the nucleus• Protons + neutrons = mass # of an

element.• Protons and neutrons are held together

by strong forces. ISOTOPE: atoms of the same element that have

a different number of neutrons

3. What is an electron?• A negatively charged particle (-)• 1/2000 AMU (almost massless)• Located outside the nucleus in an area

called the electron cloud• Equal in # to protons= at. #• They can be lost, gained, or shared with another atom.Lose e-s= atom has + chargeGain e-s= atom has - charge• Important in bonding and chemical reactions

Electron configuration

• Orbit/Energy level 1 (lowest energy) can take upto 2 e-s

• Orbit 2 can take upto 8 e-s• Orbit 3 can take upto 18 e-s

Valence Electrons

• The electrons farthest away (in outermost shell) from the nucleus are called valence electrons.

• Valence electrons are important in chemical bonds.

OQ: Which particles in matter1. provide the mass?2. occupy most of the volume?a. Electronsb. Protonsc. Electrons and protonsd. Protons and neutrons

1/29 Matterville Story

Welcome to Matterville!

Not the Addams Family!

Welcome to Matterville (where everything matters!)In the center of Matterville, there is a

place called the Nucleus Arcade, where twomembers of the Atoms Family like to hangout. Perky Patty Proton, like her sisters, isquite large with a huge smile and eyes thatsparkle (+). Patty is always happy and has avery positive personality. Nerdy NeldaNeutron is large like Patty, but she has aboring, flat mouth and eyes with zeroexpression (o). Her family is very apatheticand neutral about everything. Patty, Nelda,and their sisters spend all their time at thearcade.

Around the Nucleus Arcade, you willfind a series of roadways that are used byanother member of the Atoms Family,Enraged Elliott Electron. Elliott races madlyaround the Arcade on his bright red chrome-platedHarley-Davidson. He rides so fast thatno one can be sure where he is at any time.Elliott is much smaller than Patty and Neldaand he is always angry because these biggerrelatives will not let him in the Arcade. Hehas a frown on his face, eyes that are squintedwith anger, and a very negative (-) attitude.

The first energy street can holdonly two Electron brothers. The secondenergy street, called the Energy Freeway, can hold 8 brothers. The third energy street, called the Energy Superhighway,can hold 18 of the brothers.

The morale of Matterville is stable aslong as each negative Electron brother isbalanced out by one positive Proton sister.The number of residents in Mattervilledepends on the Proton and Neutron families.Challenge: What would happen to the moraleof Matterville if one Elliott Electron waskidnapped?

Morale of Matterville

The morale of Matterville is stable as long as it has the same number of protons (+) and electrons (-).

If someone kidnaps one Elliott Electron, the morale of Matterville would become positive (more protons).

If one Elliott Electron were to move to Matterville, the morale would be negative (more electrons).

Name: Patty Proton (p+)

Description: – Has a Happy & Positive Personality +– Larger than Electrons– # of protons = # of electrons = atomic #

Favorite Activity:– Hanging out in the Nucleus Arcade

+ +U

Name: Nelda Neutron (no)

Description: – Has a Boring Personality = No Charge or Neutral

- Larger than Electrons - Atomic Mass – Atomic # = # of Neutrons

Favorite Activity:– Hanging out in the Nucleus Arcade

0 0----

Name: Elliott Electron (e-)

Description: – Has a Negative Personality -– Smaller than P+ & No

– # of electrons = # of protons = atomic #Favorite Activity:– Hangs outside the Nucleus Arcade in the e- cloud

-\ /- ∩

The Atoms Family Songhttp://www.addamsfamily.com/addams/addams64.au

1st Verse:They’re tiny and they’re teeny,Much smaller than a beany,They never can be seeny,The Atoms Family.2nd Verse:Together they make gases,And liquids like molasses,And all the solid masses,The Atoms FamilyChorus

3rd Verse:Neutrons can be found,Where protons hang around;Electrons they surroundThe Atoms Family.ChorusChorus:They are so small.(Snap, snap)They’re round like a ball.(Snap, snap)They make up the air.They’re everywhere.Can’t see them at all.(Snap, snap)

NucleusP+&NO

1st = 2 e-

2nd = 8 e-

3rd = 18 e-

IQ: What is the charge on an atom that has 12 neutrons, 11 protons, and 11 electrons?a. Negativeb. Positivec. Neutrald. Unknown