Zusammenfassung der Ressource
Chemistry
- ATOMS
- Definition
- basic unit of matter
- cannot be created or destroyed
- Parts of an Atom
- Proton
- positively charged subatomic
particle; found in nucleus; has
mass
- Neutron
- Isotope- two or more forms of the
same element that contain equal
numbers of protons but different
numbers of neutrons
- neutrally charged subatomic particle; found in nucleus;
has mass
- Electrons
- Ion- a net electric charge due to the loss or
gain of one or more electrons.
- negatively charged
subatomic particle; found in
electron cloud; no mass
- BOHR
MODEL OF
HYDROGEN
- What is it?
- Bohr Model- a basic
model of an atom to
show placement of
protons, neutrons and
electrons
- Bohr Models are unreliable
because they are 2D reps of a 3D
object, and electron are too small
and fast to predict the actual
location
- How to read ?
- As electrons jump from excited state to
a ground state, they release energy in
waves
- Ground State- lowest energy level
- Excited state-
energized electron
- Energy released falls under electromagnetic spectrum
- ELECTRON
CONFIGURATION
- Read from left to right;
helps to locate elements,
like a road map or grid
coordinates
- Key- #: row;
Letter: block;
Superscript: # of
elements over
- Example- Electron Configuration
of Iron (Fe): 1s^2, 2s^2, 2p^6, 3s^2,
3p^6, 4s^2, 3d^6
- Noble Gas Notation
- Start from last Noble Gas passed as a way to shorten it
- Example of Selenium (Sn): [Kr] 5s^2, 4d^10, 5p^2
- VSEPR
- What is it?
- Valence Shell Electron Pair Repulsion Theory
- 3-D arrangement of molecules in an atom
- The repulsion of valence electrons cause electrons
to configure as far apart as possible
- Determined by the number of pairs bonded to the
central atom and the amount of LONE PAIRS
- Lone pairs- extra electrons on the central atom that
does not bond with another atom
- Polarity- uneven pull on the central
atom resulting in a partial positive
and negative charge
- PERIODIC TABLE
- How to read?
- Groups- vertical columns (18)
- Group 1- Alkali Metals
- Group 2- Alkaline Earth Metals
- Group Three- Transition Metals (inner/outer/post)
- Group 4- Metalloids
- Group 5- Non Metals
- Group 6- Halogens
- Group 8- Noble Gases
- Periods- horizontal rows (7)
- Periodic Trends
- Atomic Radii
- the radius of an atom from the nucleus to the edge of electron cloud
- Increases from right to left; top to bottom
- Electronegativity
- describes the ability of an atom to attract
new electrons to make new elements
- increases from left to right; bottom to top
- Ionization Energy
- describes the amount of energy
required to remove an electron from
the atom
- increases from left to right; bottom to top
- Electron Affinity
- applies to noble gases
- neutral atom's likelihood to gain an electron
- increases from left to right; bottom to top
- Oxidation Numbers
- represents the number of electrons lost (or
gained, if the number is negative) by an atom
of that element in the compound.
- 1+, 2+, 3+, +/- 4, 3-, 2-, 1-, 0
- BONDING
- Chemical Bonding- mutual electrical attraction
between nuclei and valence electrons of
different atoms
- Covalent Bond
- Between two non metals
- low melting point; low boiling point
- Ex: Carbon Dioxide
- Ionic Bond
- between a metal and
nonmetal; across staircase
- high melting and boiling point
- Ex: NaCl (salt)
- Metallic
- between two metals; sea of electrons
- High melting and boiling point
- Octet Rule- bonds increase stability;
must have 8 electrons except boron and
beryllium and hydrogen
- Single bond<double bond< triple bond
- Lewis Structures
- show the bonding between atoms of a molecule
and the lone pairs of electrons
- NAMING
- REACTION
TYPES
- Synthesis
- Add/combine
- A + B --> AB
- Decomposition
- break down
- AB --> A + B
- Single Replacemnt
- A + BC --> AC + B
- Use Activity Series-
on RT, elements can
replace elements
below it or less
reactive than it
- Double Replacement
- swap
- AB + CD --> AD+ CB
- Combustion
- O2= reactant
- Products are ALWAYS CO2 and H2O
- BALANCING
EQUATIONS
- Steps: 1. Draw line at yield sign 2. write out
all ATOMS present on both sides 3. Count
number for each side 4. Apply coefficients
to even out score (oxygen last) 5. Check
answer 6. Write ratio
- Coefficients- numbers at the front of
each atom
- Law of Conservation of Mass- matter
cannot be created, nor destroyed in a
chemical reaction
- Predicting Products- writing the product
based off of the type of reaction; girls and
boys are always paired
- STOICHIOMETRY
- Calculation of certain quantities of
reactions in a chemical reaction
- Types
- 1. Moles to
Moles
- 2. Moles to Mass
- 3. Mass to Moles
- 4. Grams to Grams
- Dimensional Analysis- step by step manner used to
solve any problem using units and numbers and
times/divide method
- Moles- 6.02 x 10^23 particles of stuff
- Avagadro's Number- 6.02 x
10^23