Please enable JavaScript.
Coggle requires JavaScript to display documents.
Stephanie Yeung Per. 3 Semester 1 (Atoms (Particle (Proton: +1,1 amu,…
Stephanie Yeung Per. 3
Semester 1
Atoms
Particle
Proton:
+1,1 amu, nucleus
Neutron:
0,1 amu, nucleus
Electron:
-1, 0 amu, electron cloud
Atomic #
= # of p+
Mass #
= p+ + n0
Isotopes
atoms of same element with different n0
Atomic mass
average of all isotopes of element
Classification of Matter
Matter
variable composition?
no
Pure Substance
Separable into simpler substances?
yes
Compound
no
Element
yes
Mixture
Uniform throughout?
no
Heterogeneous
yes
Homogeneous
Diatomic molecules:
exist as 2 of same elements in nature.
HOFBrINCl
H
ydrogen
O
xygen
F
luorine
Br
omine
I
odine
N
itrogen
Cl
orine
Periodic Table
Trends
Electronegativity:
tendency of atom to attract shared pair of e- to itself
increases
↑ →
Atomic Radius:
distance from center of nucleus to surrounding electron cloud
increases
↓ ←
Electron Affinity:
energy released when e- is added to neutral gaseous atom
increases
↑ →
Ionic Radius:
cation: smaller when lose e-
anion: bigger when gain e-
Reactivity:
force/strength of reaction
metals:
increases
↓ ← nonmetals:
increases
↑ →
Ionization energy:
energy needed to remove the valence e- from neutral gaseous atom
increases
↑ →
Effective Nuclear Charge:
finds how much shielding between nucleus and e-
Zeff = Z - S
Zeff:
atomic #
Z:
atomic #
S:
non-valence e-
# of valence e-
matches "A" column #
Properties
nonmetals:
not ductile or malleable, bad conductors, become anions (gain e-)
semimetals:
properties of metals and nonmetals
metals:
ductile (draw in wire), malleable (pressed in shape), good conductors, shiny, become cations (lose e-)
Mole relations
Mole to Particles (atoms or molecules):
Multiply mol by
6.022 × 10^23
(Avogadro's Number)
Mole to Grams:
Multiply mol by g (of element in periodic table)
Mole to Liters:
for a gas at STP, multiply mol by 22.4 L
Balancing Chemical Equations
Law of Conservation of Mass:
in ordinary chemical reactions, total mass of reactants = total mass of products
Solubility of Ionic Compounds in Water
soluble
dissolves in water (aqueous)
insoluble
forms precipitate (solid) in water
Reaction types
Decomposition
AX → A + X
Single Replacement
A + BX → AX + B
Combination (synthesis)
A + X → AX
Double Replacement
AX + BY → AY + BX
Combustion
A + O2 → CO2 + H2O
Ionic Equation
complete ionic equation
shows compounds as aqueous ion
net ionic equation
eliminates the spectator (watching) ions
Stoichiometry:
study of quantities of materials consumes and produced in chemical reactions
Percent Yield
% yield = actual yield/theoretical yield × 100
limiting reactant:
reactant that gets used up first; divide the reactant's # of mol by its coefficient in balanced equation
Significant Figures
Rules
Nonzero integers, captive zeros
always count
Trailing zeros
count if # contains decimal point
Leading zeros
do not count
Exact #s
have infinite # (1 in = 2.54 cm)
Add/Sub:
= # of decimal places in least precise measurement
Mult/Div:
= # in least precise measurement
Accuracy:
refers to agreement of particular value with true value
Unit conversion
K
ilo-
H
ecto-
D
eca-
B
ase
D
eci-
C
enti-
M
illi-
K
ings
H
ave
D
iamonds
B
ut
D
iamonds
C
ost
M
oney
Precision:
refers to degree of agreement among several measurements made in same manner
Bonding
VSEPR
Molecular Geometry
(X = bonding groups, E = lone pairs)
Bent
(AX2E2)
Trigonal Bipyramidal
(AX5)
120°/90°
Trigonal Pyramidal
(AX3E)
Seesaw
(AX4E)
Tetrahedral
(AX4)
109.5°
T-shaped
(AX3E2)
Bent
(AX2E)
Linear
(AX2E3)
Trigonal Planar
(AX3)
120°
Octahedral
(AX6)
180°
Linear
(AX2)
180°
Square Pyramidal
(AX5E)
90°
Square Planar
(AX4E2)
T-shaped
(AX3E3)
Linear
(AX2E4)
AXE
Method
X
= single bonds between central atoms and terminal atoms
E
= # of lone e- pairs on central atom
A
= central atom
steric #:
sum of
X
and
E
The
HONC
Rule
O
xygen (and Sulfur) - 2 cov bonds
N
itrogen (and Phosphorus) - 3 cov bonds
H
ydrogen (and Halogens) - 1 cov bond
C
arbon (and Silicon) - 4 cov bonds
3rd period (and below) can form more cov bonds
Molecular Polarity
polar:
bonding e- shared unequally due to diff in electronegativity of atoms
electronegativity diff: 0.3--1.7
molecular polarity
depends on type of bonds in molecule and arrangement of bonds or shape of molecule
dipole moments:
direction of polar bond in molecule; arrow points to more electronegative atom in molecule
molecular shapes:
symmetric
linear, trigonal planar, tetrahedral
nonpolar if all ends are same, polar if ends are different
asymmetric
bent, trigonal pyramidal
always polar
nonpolar:
bonding e- shared equally
electronegativity diff: 0--0.3
Rules for Drawing Lewis Structures
Put other atoms around central atom. H are always terminal. Halogens tend to be terminal.
Put e- pair between the central atom and other atoms obeying the
octet rule
.
least
electronegative
atom tends to be central atom
Put all remaining e- pairs on terminal atoms to fill to octet (H has 2 e-) If any e- pairs remain, put them on central atom. If after all pairs are put and octet rule is not satisfied, make double or triple bonds.
Add total # of valence e- and divide by 2 to get # of pairs.
The
Octet
Rule
The
octet rule
refers to the tendency of atoms to prefer to have eight electrons in the
valence shell
.
Nuclear Chemistry
Half-life:
time required for half of radioisotope's nuclei to decay into its products
mt = m0 × (0.5)n
m0 = initial mass
n = # of half-lives
mt = mass remaining
n = t/T where t = time and T = half-life
Modes of Radioactive Decay
beta decay:
parent nuclide → daughter nuclide + β particle
gamma emission:
excited nuclide → stable nuclide + photon (γ)
apha decay:
parent nuclide → daughter nuclide + α particle
positron emission:
parent nuclide → daughter nuclide + positron
electron capture:
parent nuclide + electron → daughter nuclide
Electron Orbitals
Electron Configuration Rules:
Pauli Exclusion Principle:
any single orbital may only contain e-s, but w/ opposite spin
(from: no 2 e-s may have same set of 4 quantum #s)
Hund's Rule:
e-s will fill each equal energy orbital before pairing up
Aufbau Principle:
e-s fill lowest possible energy level 1st
Orbital Shapes:
surface that contains 90% of total e- probability
(s, p, d, f)
Orbital:
region w/i energy level where there is probability of finding e-
Quantum Numbers:
Angular momentum quantum number,
l
:
orbital where e- is located
Magnetic quantum number,
m
:
orientation of e-'s orbital with respect to 3 axes in space
Principle quantum number,
n
:
shell where e- is located. # of e-s that can fit in shell is 2n^2
Spin quantum number,
s
:
behavior of e- w/i magnetic field