01/30/13 Pg 12 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 experiment c.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 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. w 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 + charge Gain 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 matter 1.provide the mass? 2.occupy most of the volume? a. Electrons b. Protons c. Electrons and protons d. 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 two members of the Atoms Family like to hang out. Perky Patty Proton, like her sisters, is quite large with a huge smile and eyes that sparkle (+). Patty is always happy and has a very positive personality. Nerdy Nelda Neutron is large like Patty, but she has a boring, flat mouth and eyes with zero expression (o). Her family is very apathetic and neutral about everything. Patty, Nelda, and their sisters spend all their time at the arcade.

Around the Nucleus Arcade, you will find a series of roadways that are used by another member of the Atoms Family, Enraged Elliott Electron. Elliott races madly around the Arcade on his bright red chrome-plated Harley-Davidson. He rides so fast that no one can be sure where he is at any time. Elliott is much smaller than Patty and Nelda and he is always angry because these bigger relatives will not let him in the Arcade. He has a frown on his face, eyes that are squinted with anger, and a very negative (-) attitude.

The first energy street can hold only two Electron brothers. The second energy 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 as long as each negative Electron brother is balanced out by one positive Proton sister. The number of residents in Matterville depends on the Proton and Neutron families. Challenge: What would happen to the morale of Matterville if one Elliott Electron was kidnapped?

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 (n o ) 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

Name: Elliott Electron (e - ) Description: – Has a Negative Personality - – Smaller than P + & N o – # of electrons = # of protons = atomic # Favorite Activity: – Hangs outside the Nucleus Arcade in the e- cloud -\ /- ∩

The Atoms Family Song 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 Family Chorus 3rd Verse: Neutrons can be found, Where protons hang around; Electrons they surround The Atoms Family. Chorus Chorus: 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)

Nucleus P+ & N O 1 st = 2 e- 2 nd = 8 e- 3 rd = 18 e-

IQ: What is the charge on an atom that has 12 neutrons, 11 protons, and 11 electrons? a.Negative b.Positive c.Neutral d.Unknown