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chloe ko.
christina chow.
mr. doktor's chemistry class
block g

home. mrdoktor.

• elements close to each other on the periodic table display similar characteristics
• There are 7 important periodic trends

1. reactivity
2. ion charge
3. melting point
4. atomic radius
5. ionization energy
6. electronegativity
7. density

~Reactivity~

• metals and non-metals show different trends
• the most reactive metal is Francium; the most reactive non-metal is Fluorine

~Ion Charge~

• elements ion charges depend on their group (column)

• elements in the center of the table of the highest melting point
• noble gases have the lowest melting points
• starting from the left and moving right, melting point increases (until the middle of the table)

• raidus decrease to the up and the right
• helium has the smallest atomic radius
• francium has the largest atomic radius

• ionization energy is the energy needed to completely remove an electron from an atom
• it increases going up and to the right
• all noble gases have high ionization energy
• helium has the highest ionization energy
• francium has the lowest ionization energy
• opposite trend from atomic radius

• electronegativity refers to how much atoms want to gain electrons
• same trend as ionization energy

 Isotopes and Atoms


Atomic Number - the number of protons

atomic mass - atomic # = # of neutrons 
 ( p + n )    -    (p)    =       (n)

Isotopes - have the same atomic number but different mass

Example:

Isotope	Mass Number	Atomic Number	Number of Protons	Number of Neutrons
88 Sr	88	38	38	50
16 O	16	8	8	8
89 Y	89	39	39	50

Mass Spectrometers:
-are used to determine the abundance and mass of hte isotopes of elements
-device known as a mass spectrometer can be used to determine the relative abundance and the mass of the isotopes of elements

~christina chow :]

Bohr Theory

• The electron is a particle that must be in orbital in the atom

Quantum Theory

• The electron is like a cloud of negative energy or a wave
• Oribtals are ares in the 3D space where the electrons most probably are
• The energy of the electron is in its vibrational modes-like notes on a guitar string
• Photons are produced when high energy modes change to lower energy mode

S Orbitals

• There is 1 suborbitals
• Each orbital holds 2 electrons
• Total electrons = 2

P Oribtals

• There are 3 suborbitals
• Each contain 2 electrons
• Total electrons = 6

 D Orbitals

• There are 5 suborbitals
• Each contains 2 electrons
• Total electrons = 10

F Orbitals

• There are 7 suborbitals
• Each contains 2 electrons
• Total electrons = 14

example:
how many and what type of electrons does Potassium have?
1s^2 2s^2 2p^6 3s^2 3p^6 4s

Atoms that have the same electronic formation are called isoelectronic.

~Chloe ^_^

Drawing Bohr Diagrams

Draw a  Bohr Diagram for the element K.
19 Potassium +         protons= 19
          39                  atomic mass= 39
                                neutrons=20













Why does K form an ion with a 1+ charge?
Potassium forms an ion with a 1+ charge because it needs to loose an extra protons to
 make it have a full valence shell.

Draw a  Bohr Diagram for the element S.
16 Sulphur 2-   protons= 16
      28.0           atomic mass= 28
                       neutrons= 12










Why does S form an ion with 2- charge?
Sulphur has a charge of 2- because it need two more electrons in order to have a full valence shell.


-Atoms are elctrically neutrl
-2 different models can be used to describe electron configuration
    -energy level model
   -Bohr Model
-Electrons occupy shells which are divided into orbitals
     -2 e- in the first orbital
     -8 e- in the second orbital
    - 8 e- in the third orbital

eg. Beryllium
      2e-
     2e-
9-4 BE

~christina chow :]

• Bohr (1920s)

Rutherford's model was inherently unstable
-Protons and electrons should attract each other
Matter emits light when it is heated (blackbody radiation)
Light travels as photons
The energy photons carry depends on their wavelength
-Bohr based his model on the energy (light) emitted by different atoms
-each atom has a specific spectra of light
Bohr's Theory
-electrons exist in orbitals
-when they absorb energy they move to a higher orbital
-as the yfall from a higher orbial to a lower one they release engery as a photon of light




Atomic Theory

Aristole [European view]:
Four element theory (water, earth, wind, and fire)
- the four element theory lasted around 2000 years
- it is not a scientific theory because it could not be tested against observation

Democritus [European view]:
- in 300 B.C Democritus said atoms were indivisble particles
- first mention of atoms [atomos]
- it is not a testable theory, only a conceptual model
- he didn't know any atomic nucleus or its constituents
- cannot be used to explain chemal reactions

Lavoisier [late 1700s]:
- the law of conservation of mass
-law of definite proportions
   '---> water is always 11% H & 89% O

Proust [1799]:
-if a compund is broken down into its constituents, the products exist in teh same ratio as in the compoun
-experimentally proved Lavoisier Laws

Dalton [early 1800s]
-atoms are solid, indestructible spheres [like Billard Bas]
-provides for different elements (these would be different spheres)
-based on the law of conservation of mass











Haveing a molecule (atoms combine in simple whole number ratios) explains the law of constant composition

If the atoms are not destroyed then the mass does now change
 eg.















J.J Thomson [1850s]:
- raisin bun model
- solid, positive spheres, with negative particles embedded in them
- first atomic theory to have positive (protons) & negative (electrons) charge
- demonstrated teh existence of electrons using a cathode ray tube

Rutehrford [1905]:
- showed taht atoms have a positive, dense center with electrons outside it
- resulted in a planetary model
- explains why electrons spin around the nuclues
- suggests atoms are mostly empty space

~christina chow :]

In class today we just did our first chapter test.

~Christina Chow :]

Our chemistry test was suppose to be having our first chapter test today but instead it will be next class. We just reviewed on naming ionic formulas, balancing word equations, classifying physical and chemical changes. We also finished our lab on sodium chloride. Mr. Doktor told us the accurate results of how much grams of sodium chloride can dissolve in 200mL of water.



Today we did our first lab on sodium chloride. The purpose of the lab was to see the maximum amount off Sodium Chloride (Table Salt) we can dissolve in 10mL, 20mL, 30mL and 40mL of water. We poured salt onto the weight paper which was on the scale. Then we moved it to the beaker full of measured water. We stirred constantly with a glass rod, and added more salt until the salt didn't dissolve anymore. We recorded our amount of salt onto our charts by pressing the zero buttoning every time so we get a accurate mass of salt we used.

CHLOE KO