Unit+3


 * Atomic Theory**

First identified atoms Classified atoms as:
 * Democritus and Aristotle -**
 * All matter is made up of invisible particals
 * There is a void which is empty space between atoms
 * Atoms are completely solid
 * Atoms are homogenous, which is no internal structure
 * Atoms vary in size, shape and weight

He is known as the father of the atomic theory This atomic theory says:
 * John Dalton-**
 * Chemical elements are made up of several atoms
 * The atoms of elements are identical in their masses
 * Atoms of different elements have different masses
 * Atoms combine in small whole number ratios
 * Atoms, like matter, can neither be created nor destroyed

His model is called Plum Pudding Verified that atoms are divisible In his model: He used cathode tube to complete his research The negative particles were later named electrons
 * J.J Thomson-**
 * Pudding was the positive
 * Plum was the negative

Discovered the charge of an electron to be negative. He did the research by using an oil drop expirement. Because the oil drops fell throuh a positivley-charged plate he could concluded that they were negative. This supports the common phrase "opposites attract"
 * Robert Millikan-**

Ernest Rutherford- His research used gold foil. He wast trying to support the research of J.J Thomson and expected to seethe atom as "plum pudding" However, he found that the alpha particles (positively charged particles) reflected when passed through an atom. His research showed:
 * An atom's space is mostly occupied be electrons.
 * The center of the atom is known as the nucleus.
 * He called the positive parts protons.

He worked with and for Ernest Rutherford. He focused his work on the hydrogen atom. Problems with his idea were: We'll use his idea of ground state electrons and excited state electrons.
 * Niel's Bhor-**
 * That his work only worked with hydrogen.

His research helped explain mass total of an atom. He research solidified Rutherford's. He discovered the neutron.
 * James Chadwick-**

N= Energy level (0-7) L= Orbital (0=S, 1=P, 2=D, 3=F) M(l)= Spacial orientation (S:0,/ P:-1,0,1/ D:-2,-1,0,1,2/ F:-3,-2,-1,0,1,2,3) M(s)= Electron Rotation (1/2= up, -1/2=down)
 * Quantum Numbers-**

1. What is the quantum number for copper? Answer: 3, 2, 2, 1/2. Copper is in the 3rd energy level, in orbital D, Special orientation 2, and its electron rotation is 1/2. ** 2. Who use Plum Pudding to figure out the charges? Answer: J.J Thomson
 * Practice Problems-