====== Notes on Primrose Kitten Chemistry======

Memorize these:

|carbon dioxide|CO<sub>2</sub>|
|water|H<sub>2</sub>O|
|oxygen gas|O<sub>2</sub>|
|hydrogen gas|H<sub>2</sub>|
|nitrogen gas|N<sub>2</sub>|
|ammonia|NH<sub>3</sub>|
|hydrochloric acid|HCl|
|sulfuric acid|H<sub>2</sub>SO<sub>4</sub>|

Equations

nitrogen gas + hydrogen gas -> ammonia\\
H<sub>2</sub> + N<sub>2</sub> -> NH<sub>3</sub>\\
balanced equation: N<sub>2</sub> + 3H<sub>2</sub> -> 2NH<sub>3</sub>\\

methods of separating mixtures
  * distillation, separate liquids with different boiling points
  * evaporation, separate liquids from solids
  * filtration, separate liquids from solids
  * fractional distillation, separate by different sizes and boiling points

1908-1913: Working under Rutherford, Geiger and Marsden executed the Gold Foil experiments at the University of Manchester.
Before this, we had plum pudding model of an atom.  Positive and negative charge was distributed uniformly throughout a substance.
Fired an alpha particle at a gold foil.  Most particles went right through.
Some were deflected.  Some bounced back.
From this, they deduced that each atom has a nucleus where all positive charge and most mass is clustered.

1932: Chadwick discovered the existence of neutrons, also working under Rutherford.

Periodic Table\\
Groups give us number of electrons in the outer shell\\
Periods give us number of shells\\

Na, sodium has 11 electrons, 2,8,1\\
The single electron has a tendency to wander off, leaving an ion with 10 electrons.\\

F, florine, has 9 electrons, 2,7\\
The outer shell is short one electron, so it tends to gain one.\\

Sodium floride 

Elements in group 1 tend to form +1 ions\\
group 2: +2 ions\\
group 6: -2 ions\\
group 7: -1 ions\\
group 8: stable\\

metals on the left-hand side form positive ions\\
non-metals, right-hand side, from negative ions\\

1863, 56 known elements, new elements discovered at one per year

1868: Mendeleev developed the first proper periodic table. He saw it in a dream.
published in textbook <i>Principles of Chemistry</i> (two volumes, 1868–1870)
  * by mass
  * left gaps, able to predict missing elements
  * groups by similar properties

|group 8 or 0|noble gasses|unreactive|full outer shell|increased boiling point as you move down the group|
|group 1|alkali metals|very reactive|only 1 electron on outer shell|reactivity increases as you move down the group|
|group 7|halogens|very reactive|7 electrons on outer shell|generally found in diatomic molecules (F<sub>2</sub>, Cl<sub>2</sub>, Br<sub>2</sub>) Florine gas, Chlorine gas, Bromine gas; reactivity decreases as you move down the table, melting points and boiling points increase; more reactive halogens will displace less reactive halogens in a reaction|

transition metals\\
typical\\ 
properties: hard, shiny, conductive of heat and electricity\\
can be used in building bridges, saucepans, wires\\
copper: blue\\
iron (ii): green\\
iron (iii): red/brown\\