Today in ScienceYou will Need:1)Pencil, Colored Pencils, Highlighters or Markers2)Power Notes – Atomic Structure– 2 page 3 sides-Bookshelf- Please Staple

Topic: Power Notes- Atomic Structure

Do we understand everything????

Democritus 400 BC

Lavoisier 1789

• 1st idea of “atoms”• Believed all matter is made

up of tiny particles separated by space

• Called particles “atomos” which means indivisible.

• Founder of modern chemistry

• 1st carefully controlled experiments providing evidence to the Law of Conservation of Mass

France - provided the formula for the conservation of matter in chemical reactions, and also distinguished between an element and a compound

Greece - stated that all matter is made up of atoms.  He also stated that atoms are eternal and invisible and so small that they can’t be divided, and they entirely fill up the space they’re in

Dalton 1766-1844 1st MODERN Atomic Theory1.All matter made up of tiny indivisible particles called atoms2.Atoms of the same element have identical properties3.Atoms of different elements have different properties4.Atoms combine in a specific ratio to form compounds5.A specific compound is always made up of atoms in a specific proportion.

England - formed the 1st atomic theory, which states that all matter is composed of tiny, indestructible particles called atoms that are all alike and have the same atomic weight. 

Thomson 1897

Rutherford 1898

Plum Pudding Model1.Negative particles scrambled into the “dough” of the positive particles.

Gold Foil Experiment1.Atoms are mostly empty space2.All the Mass of an atom is in the positively charged ball in the center of the structure.

England - discovered the electron and developed the plum-pudding model of the atom.

England - used the results of his gold-foil experiment to state that all the mass of an atom was in a small positively-charged ball at the center of the atom. 

Rutherford Continued

• Top(RED): Expected results: alpha particles passing through the plum pudding model of the atom undisturbed.Bottom (YELLOW): Observed results: a small portion of the particles were deflected, indicating a small, concentrated positive charge. Note that the image is not to scale; in reality the nucleus is vastly smaller than the electron shell

Bohr 1922

Schroedinger 1930

“Planetary” atom model1.Believed the atom structure was like our solar system2.Nucleus in the middle like the sun and the electrons orbiting like the planets.

Wave Mechanic Model1.Planetary model was too specific2.Rather: electrons vibrate around the outside of the nucleus- can only predict where they are most like to be3.QUARKS – protons, neutrons and electrons made up of some of these smaller particles.4.http://library.thinkquest.org/05aug/01087/quarks.html

Denmark - stated that the electrons moved around the nucleus in successively large orbits. He also presented the Bohr atomic model which stated that atoms absorb or emit radiation only when the electrons abruptly jump between allowed, or stationary, states. 

Austria - introduced the Shroedinger Equation, a wave equation that describes the  form of the probability waves that govern the motion of small particles and how these waves are altered by external influences.

Basic Atomic Structure

Bohr Model for Lithium(not to scale)

Where is most of the mass in the Atom?

Where is most of the volume in the Atom?

Today scientist agree on the three basic subatomic particles that make up all atoms.

P= 3 +N = 3 0

Electron = 3

NUCLEUS

Outside the Nucleus; Electron Cloud

Nucleus

Electron

• Contains protons(+) and Neutrons (0)

• Holds most of the mass of the atom

• Very small compared to the entire size of the atom

• Most dense part of the atom

• Negatively charged subatomic particle

• Found outside the nucleus in the electron cloud

• Smallest particle; mass = 1/1836th of the atom

Proton

Neutron

• Positively charged subatomic particle• Found in the nucleus• Mass = 1 amu (atomic mass unit)• # of protons in an atom IDENTIFIES the

atom (which element)• Each element has its own unique # of

protons- change the proton count: change the element

• # of protons in the nucleus of an atom called the atomic number

• Zero charge• Mass = 1 amu• Do NOT affect the identity of the atom• Found in the nucleus• Same atom of an element can have

varying amounts of neutrons (isotope)• Adding the total number of protons &

neutrons = Atomic Mass Number

http://www.sawyerscience.com/Units/unit2/atoms_compounds.html

Isotope

Ion

• Atomic Number : • # of protons• # of electrons if atom is neutrally

charged• Chemical Symbol:• Element abbreviation• Some based on Latin names

• Element Name:• There in case you forget

• Atomic Mass:• Sum of the particles in the nucleus

(protons & neutrons)• Can change with isotopes of the same

element• Represents an AVERAGE MASS

Same # of protons (same element); different # of neutrons

Charged particle; electrons vary

3

LiLithium

6.9

Homework1)Complete Power Notes– Due Tomorrow