Unit+3

John Dalton’s Atomic Theory states that: 1. All matter consists of indivisible matter: atoms 2. Atoms of one element cannot be converted into atoms of another element 3. Atoms of an element are identical in mass and other properties 4. Compounds result from the chemical combination of specific ratios of different elements 5. Explains mass laws

JJ Thomson: • Used cathode rays • Proposed plum pudding model • Compared mass to charge ratios

Robert Millikan: • Measured charge of the electron with the oil drop test Ernest Rutherford: • Conducted gold foil experiment which proved that the atom has a positively charged nucleus James Chadwick: • Research helped explain mass number of an atom • Discovered neutron

Niehl’s Bohr: • Focuses on hydrogen atom • Problem was it only worked with hydrogen atoms

Proton- A subatomic particle found in the nucleus that has a unit positive charge (p+) Neutron- A subatomic particle found in the nucleus, with a mass slightly greater than that of a proton (n0) Electron- A subatomic particle that possesses a unit negative charge and occupies the space around the atomic nucleus (e-)

Electron Configuration- The distribution of the electrons within the orbitals of the atoms of an element; also the notation for such a distribution Orbital Diagram- A depiction of electron number and spin in an atom's orbitals by means of arrows in a series of small boxes, lines, or circles

Quantum Theory- A modern model of the atom Quantum Numbers- 1st: principal quantum number "n" tells what energy level the electron is in. As "n" increases, the distance from the nucleus increases. 2nd: "L" tells the shape of the orbital. "L"= s,p,d,f s=spherical p=dumbbell d=combination of "X" shaped orbitals and lifesaver f=complex shapes S=0 P=1 D=2 F=3 3rd: "Magnetic quantum number" "ml" tells the spatial orientation of the orbital. The subshell in which the final electron falls represents the ml. The middle subshell is zero, and the other subshells are represented by their distance from the middle one. 4th: "spin quantum number: "ms " either +1/2 or -1/2 or up arrow or down arrow If the final electron is an up arrow, it's a positive 1/2.If it's a down arrow, its a negative 1/2.

Atomic Mass- Decimal point on periodic table, of an element Gram- measurement of a mole of atoms Mole- base comparison of all types of elements Molecule- A structure consisting of two or more atoms that are chemically bound together and behave as an independant unit

Review Problems-

1. Who is credited with discovering the atomic nucleus? A. Dalton B. Gay-Lussac C. Thomson D. Milikan E. Rutherford

2. Rutherford bombarded gold foil with alpha particles and found that a small percentage of the particles were deflected. Which of the following was not accounted for by the model he proposed for the structure of atoms? A. The small size of the nucleus B. The charge on the nucleus C. The total mass of the atom D. The existence of protons E. The presence of electrons outside the nucleus

3. Who is credited with first measuring the charge of the electron? A. Dalton B. Gay-Lussac C. Thomson D. Milikan E. Rutherford

4. What is the electron configuration of Hydrogen? A. 800000s3 9d7 1u90 B. 1s2 C. 1s1 D.1s2 2s2 3p6

5. What is the "n", "l", "ml", and "ms" of Chlorine. a. 3, 1, 0, -1/2 b. 2, 2, 5, 1/2 c. 2, 2, 5, -1/2 d. 3, 2, 3, 1

6. What is the "n", "l", "ml", and "ms" of N?

a. 3,2,1,-1/2 b. 2,1,1,+1/2 c.1,2,1,+1/2 d. 2,1,1,+1/2

Review Problem Answers-
 * E
 * C
 * D
 * C
 * A
 * B