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James Su 2e7af7e925 Update Unit 1: Chemistry Part 1.md

2019-10-21 00:13:55 +00:00

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Unit 1: Chemistry

Matter: has mass, takes up space.
- fundamental unit -> ATOMS
One formula unit - repeating strucure in an ionic compound that has the simplest ratio of ions in the compound
- Can be represented in Chemical Formula (e.g $`Li_3P`$ )
Ions are particles with charges
Models: Allows people to make accurate predictions about behavior of MATTER.
Atom: Smallest unit of element that still retains its properties. Made of subatomic particles
Atomic mass unit: $`1.67 \times 10^{-27}kg`$

Atoms

Atoms are the smallest unit of an element that still retains its properties
Atoms are made of subatomic particles
Relative Charge: compared to something.
AMU = atomic mass units
atmoic notation $`_{19}K`$
an isotope is an atom (or atoms) of an element with a unique # of neutrons

Name	Symbol	Relative mass (amu)	Location	Relative Charge
Protons	$`p^+`$	$`1`$	nucleus	$`+1`$
Neutrons	$`n^0`$	$`1`$	nucleus	$`0`$
Electrons	$`e^-`$	$`~\dfrac{1}{2000}`$	in orbit around nucleus (shell, energy level)	$`-1`$

IUPAC

Letter	Definition
I	International
U	Union
P	Pure and
A	Applied
C	Chemistry

Involved in studying, varifying information (eg the periodic table -> Describes the elements -> pure susbtances made of only one kind of atom),and publishing.
Standarize the information for the public

Bohr Rutherford

Electrons in uncharged atom, # protons $`=`$ # electrons
Mass of an atom is the weighted average if akk usitioes if element
Atomic Notation, Top number is the mass, bottom number is the atomic number.

Lewis Structures (dot diagrams)

shows valence $`e^-`$ ; centre is atomic symbol
Use family groups to figure out valence $`e^-`$

Trends on the Periodic Table

Periodic Table: Describes elements pure susbatances made of only 1 type of Atom.
The further away the electron is from the nucleus, the more energy it has.
Periods: repeating pattern.
Metals on bottom left, non-metals on top right

Measuring Atomic Radius

Stack a bunch of them, measure, divide by number of atoms, easy clap :p.

Trend	You move along a period (row) from left to right	you move down a group (column) from top to bottom
Number of valence electrons and electron shells	Valence shells stays the same, while electrons increases	Valence shells increases, while electrons stays the same
Atomic Radius (size of an atom)	Decrease due to more protons in the nucleus that attract the electrons, while having the same atomic radius	Increases due to shielding and more energy levels, which actually cancels out and is greater than the force of increasing protons in the nucleus
Reactivity of group 1 + 2 metals (i.e How likely are they to lose electrons?)	Decreases due to smaller atomic radius and more protons in the nucleus	Increases due to larger atomic radius
Reactivity of non-metals (Ie. How likely are they to gain electrons?)	More likely to gain electrons, more protons in nucleus and stronger hold on them	More likely to gain electrons, more protons in nucleus and strong hold on them

Rows

Same energy level in each period
Same number of valence electrons in each group
Across a row/period $`\rightarrow`$ more $`p^+`$ in nucleus $`\rightarrow`$ greater attraction to $`e^-`$
Atomic radius decreases as you move acroos a row/period, due to more protons in the nucleus that attract the negatives.
Atomic radius is the from the center of the atom (nucleus) to the outer most shell (valence shell)

Columns

down a column, increase of energy level, as you move down
every atom has only one valence shell (cause its the most outer shell)
if valence shell is further away from the nucleus, less attractive force between nucleus and valence $`e^-`$
more energy levels where $`e-`$ can be
Negative electrons are repeling the valence shell electrons (shielding)
Shielding “inner electrons” repel valence electrons and “block” attraction force between valence electrons and nucleus
Atomic radius increases as you move down a column/group

Metals

They tend to lose electrons
They are shiny, ductile, malleable, conductive
They have a weak/loose hold on electrons
Most metals are considered to be multi-metals (multi-valent)
- can form ions of differing charges
- add roman numerals to the ions name to indicate its charge, for example, iron( $`III`$ ) oxide.
Metalloids: non-metals with same metallic or metals with non-metalic properies`

Non-Metals

They are dull, bad conductors - insulators
Tend to gain electrons
The have a strong hold on electrons
Usually non-ductile nor malleable

Bonds

An ionic bond is a bond between a negative ion and a positive ion (so a anion and a cation)
An convalent bond is a bond between 2 non-metals
An ion is a charged particle
An anion is formed when an particle gains electrons
An cation is formed when an particle loses electrons
We can use modesl(e.g Lewis dot diagrams) to show bonding
Atoms will lose or gain electrons to achieve noble gas $`e^-`$ configuration $`\rightarrow`$ The most common stable ion. (eg, if $`Na`$ loses electrons, it becomes like $`Ne`$ , if $`Cl`$ gains an electron, it becomes like $`Ar`$ )
To show that atoms are different than ions, we put square brackets around it $`[Na]`$ , then we put superscript on the top right to show its charge, $`[Na]^+`$ (if the charge is only a $`\pm 1`$ , we just put a $`+`$ instead of $`1+`$ )
Example of ionic bond:

Non-Metal Ionic Names

Element	Name
Hydrogen	Hydride
Boron	Boride
Carbon	Carbide
Nitrogen	Nitride
Oxygen	Oxide
Fluorine	Fluoride
Silicon	Silicide
Phosphide	Phosphide
Sulfur	Sulphide/Sulfide
Chlorine	Chloride
Arsenic	Arsenide
Selenium	Selenide
Bromine	Bromide
Tellurium	Telluride
Iodine	Iodide
Astatine	Astitide

Chemical Nomenclature

Naming and writing chemical formuals
According to IUPAC
Direct relationship beween chemical name and chemical structure
- Going down diagonally from aluminium, we get a pattern of $`3+`$ , $`2+`$ , $`1+`$ of charge. Aluminium has a charge of $`3+`$ , Zinc has a charge of $`2+`$ , and silver has a charge of $`1+`$ , and they are all mono-valent. (not multi-valent)
  - Galvanize (rust $`\rightarrow`$ white shield $`\rightarrow`$ cover iron $`\rightarrow`$ prevnet rusting, but I don’t think it will be in this unit)

Formula	Name
$`NaCl`$	Sodium chloride
$`K_3P`$	Potassium phosphide
$`Mg_3P_2`$	Magnesium phosphide

Polyatomic Ions

Ions that are made of $`\ge 2`$ atoms.
Molecules with a charge
eg. $`CaCo_3`$
- $`Ca \rightarrow`$ Calcium ion $`Ca^{2+}`$ (Cation)
- $`CO_3 \rightarrow`$ Carbonate ion $`CO_3^{2-}`$ (Anion)
- Calcium carbonate
The ones that are not multi-valent are:
- The first 20 elements
- alkali metals
- alkaline earth metals
- non-metals (the ones hugging the staircase are also non-metals (some of the metalloids))
- halogens
- noble gases
If there is more than one polyatomic ion in a formula unit, then surround the ion with brackets/parentheses
Oxyanion are negative ions with oxygen in them

Polyatomic Ion Name	Formula (Always Remember The Charge!)
Ammonium	$`NH_4^+`$
Acetate	$`CH_3COO^-`$
Borate	$`BO_3^{3-}`$
Chlorate	$`ClO_3^-`$
Cyanide	$`CN^-`$
Hydroxide	$`OH^-`$
Nitrate	$`NO_3^-`$
Permanganate	$`MnO_4^-`$
Carbonate	$`CO_3^{2-}`$
Chromate	$`CrO_4^{2-}`$
Dichromate	$`Cr_2O_7^{2-}`$
Sulfate	$`SO_4^{2-}`$
Phosphate	$`PO_4^{3-}`$

Oxyanions

Nitrate
Borate
Carbonate
Chlorate
Sulfate
Phosphate
And their family members :p.

Deriving Ions From Parent

Polyatomic Ion Name	Operation	Chemical Formula
Perchlorate	(add one extra oxygen to the parent)	$`ClO_4^-`$
Chlorate	(parent)	$`ClO_3^-`$
Chlorite	(has one less oxygen than the parent)	$`ClO_2^-`$
Hypochlorite	(has two less oxygens than the parent)	$`ClO^-`$

Note that the charge remains the same
Polyatomic ions in the same group on the periodic table form similar polyatomic ions

Chlorate	$`ClO_3^-`$
Bromate	$`BrO_3^-`$

Acidic Oxyanions

Acids generall have hydrogen ions $`(H^+)`$
Acidic Oxyanions $`\rightarrow`$ Negatively charged ion with $`O`$ and $`H`$
Each hydrogen added to a polyatomic ion increases the charge by one, and changes the name:

Name	Chemical Formula
Hydrogen carbonate ion	$`HCO_3`$
Dihydrogen phosphate ion	$`H_2PO_4^-`$
Monohydrogen phosphate ion	$`HPO_4^{2-}`$
Hydrogen Sulfate	$`HSO_4^-`$
Hydrogen Carbonate	$`HCO_3^-`$

For above, we use mono for phosphate to avoid ambigious cases, where $`H_2PO_4^{-}`$ and $`H_2PO_4^{2-}`$ are the same if we don’t put mono infront. As for the Hyrogen carbonate ion we don’t put a mono due to no ambigious cases.

Molecular Compounds

Are not made of ions, instead molecules
Shared pair of electrons -> covalent bonds
Lone pair of electrons are electrons that are not shared
Radicals are atoms with unpaired electrons, very reactive
Molecules have no charge
Atoms fill their valence shells to form molecules
Double bond between oxygen atoms in an oxygen molecule

Properties Of Ionic And Molecular Compounds

Compound	State at Room Temperature	Solubility In Water	Colour of solution	Conductivity Of Solution	Ionic Or Molecular
ammonium chloride	solid	soluble, overtime the substance starts to get smaller and disappears	colourless	conductive	ionic
copper $`(II)`$ sulfate	solid	soluable	blue	conductive	ionic
sodium chloride	solid	soluble	colourless	conductive	ionic
calcium hydroxide	solid	slightly soluable	white	slightly conductive	ionic
sodium hydroxide	solid	soluble	colourless	conductive	ionic
sucrose	solid	soluble	colourless	not conductive	molecular
iodine	solid	not soluble	yellow	not conductive	molecular
hydrochloric acid	aqueous	soluble	colourless	conductive	molecular
ethanol	liquid	soluble	colourless	nont conductive	molecular
nitrogen gas	gas	N/A	N/A	N/A	molecular
carbon dioxide (dissolved in water)	gas	slightly soluble	colourless	a tiny bit conductive	molecular

Generalizations

Classification of substances	Phase at room temperature	Solubility in water	Colour of solution	Conductivity of solution
Ionic	Solid	Soluble	colourless, white	Conductive
Molecualr	liquid, gas, or solid	non-soluble	Has distinct colour?	Not really conductive

Binary Molecular Compounds

2 different kinds of atom in molecule
- Eg. $`CO_2 \rightarrow`$ Carbon Dioxide $`\rightarrow`$ 2nd atom has ide.
- $`CO \rightarrow`$ Carbon Monoxide $`\rightarrow`$ If 1st atom is mono, drop mono

Greek Prefix For Number Of Atom

Prefix	Name	Preifx	Name
1	mono	6	hexa
2	di	7	hepta
3	tri	8	octa
4	tetra	9	nona
5	penta	10	deca

Diatomic Molecules The gens, Hydrogen, Nitrogen, Oxygen, Halogen

Common Names

$`NH_3 \rightarrow`$ Ammonia
$`H_2O \rightarrow`$ Water
$`CH_4 \rightarrow`$ Methane

Elements found As Molecules In Nature

$`H_{2(g)}, Cl_{2(g)}, Br_{2(g)}, I_2, N_2, O_2, F_2`$

Chemical Formula	Lewis Structure	What does the molecular model look like?	Name
$`H_2`$			Hydrogen
$`O_2`$			Oxygen
$`N_2`$			Nitrogen
$`I_2`$			Iodine
$`H_2O`$			Water
$`NH_3`$			Ammonia
$`CO_2`$			Carbon dioxide
$`SBr_2`$			Sulfur dibromide
$`O_3`$			Ozone
$`CF_4`$			Carbon tetrafluoride
$`SiH_4`$			Silicon tetrahydride
$`OH^-`$			Hydroxide ion
$`H_3O^+`$			Hydrodium ion