10Th Chap 4,5 Chemistry

Front 1

Def. of Atom

Back 1

- smallest unit of matter;

Front 2

Democritus’ Atomic Philosophy-

Back 2

-atoms were indivisible, indestructible
-matter composed of indivisible particles and empty space

Front 3

Dalton’s Atomic Theory- The Postulates

Back 3

1. All matter consists of atoms
2. Atoms of one element can’t be converted to atoms of another
3. Atoms of an element are identical in mass but different than another element
4. Compounds result from chemical combination of specific ratio of atoms

Front 4

Dalton's theory explains mass laws

Back 4

- atoms can’t be created/destroyed, or converted to different types of atoms,
-every atom has fixed mass, chem.
-Reaction atoms are combined but mass doesn’t change

Front 5

Modern Atomic Theory

Back 5

1. All matter composed of atoms
2. Atoms cannot be subdivide, created, destroyed except in nuclear reactions
3. Atoms of an element differ in proportion from atoms of another element
4. Atoms of an element have a characteristic average mass unique to element

Front 6

Discovery of the Electron

Back 6

-J J Thomson, 1897 used cathode ray tube to deduce the presence of negative charged particle (electron)

Front 7

Mass of Electron

Back 7

-Robert Milliken 1909 determines mass of electron 9.109 time 10^-31

Front 8

Atomic Scale

Back 8

-Most mass of atom is in nucleus, electrons are found in outside of nucleus,

Front 9

Thomason’s Atomic Model

Back 9

-believed that electrons were like plums embedded in a positively charged “pudding”

Front 10

who discovered nucleus

Back 10

Rutherford- bounced off of gold leaf, something else in atom besides electrons (nucleus is small and dense,

Front 11

Atomic Number-

Back 11

(Z) tells the number of protons and electrons in the element

Front 12

Mass Number-

Back 12

(A) number of protons and neutrons in nucleus of an isotope

Front 13

Isotopes

Back 13

- elements have natural mixtures of isotopes; atoms of same element that different in number of neutrons

Front 14

Atomic mass is an...

Back 14

-average of naturally occurring isotopes of that element
-Find: (atomic mass) (percent) + (atomic mass) (percent)= average

Front 15

Bohr Model of the Atom

Back 15

- electrons orbit nucleus like planets orbit sun
1. The H atom has only certain allowable energy levels
2. The atom does not radiate energy while in one of its stationary states
3. The atom changes to another stationary state (electron moves to another orbit) absorbing or emitting a photon

Front 16

Noble gases
def.
the 6 of them
use them for

Back 16

-all shells are filled stable (He, Ne, Ar, Kr, Xe, Rn)
- use noble gas closer to another gas
[He]...

Front 17

Bohr Limitations

Back 17

- failed to predict spectrum of any atom beside H
-only works for one electron species;

Front 18

Quantum Mechanical model-

Back 18

-describes an atom with certain allowed wave like motion of an electron whose exact location is impossible to know

Front 19

Orbital
def.
probability...
has a meaning...

Back 19

-region within an atom w/ a probability of finding an electron;
-shapes defines surface w/ 90% of a total electron;
-mathematical function with no physical meaning

Front 20

Quantum Numbers

Back 20

- gives electron identity (4)

Front 21

Principal quantum number-
letter symbol
def
equation

Back 21

-(n)
-denotes shell level where electron is located,
-number of electrons- 2n^2

Front 22

Angular momentum (l)

Back 22

-shapes of the orbital sub shell in which electron is located

Front 23

shapes of
L=0
L=1
L=2
L=3

Back 23

s-shaped (sphere)
p-shaped (peanut)
d-shaped
f-shaped

Front 24

Magnetic quantum number-
letter symbol
def.
ex.

Back 24

(ml)
-denotes orientation of the electron orbital w/ respect to 3 axis in space
-(sphere lies on all 3 axis)

Front 25

to find each of these
Angular momentum l (shape)
Magnetic (orientation)
Spin Quantum number

Back 25

0 -> n-1
–L, 0, +L
½ and -½

Front 26

Aufbau Principle

Back 26

- Electrons are added one at a time to the lowest energy orbital- go up to 2 electrons

Front 27

Pauli Exclusion Principal

Back 27

- orbital holds 2 electrons and spins in opposite direction

Front 28

Hund’s rule

Back 28

- electron occupies equal energy orbital; electrons go into one orbital before pairing

Front 29

Transition elements-

Back 29

Irregular configuration Cr and Cu
one electron in an orbital is more stable than a full orbital

Front 30

electrons in each shape

Back 30

S=2
P=6
D=10
F=14

Front 31

Order of orbitals

Back 31

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d

Front 32

energy level sets

Back 32

|1s|
|2s, 2p|
|3s, 3p|
|4s, 3d, 4p|
|5s, 4d, 5p|
|6s, 4f, 5d, 6p|
|7s, 5f, 6d|