chem 1211 acs final
bond order
# of bonds / # of connections
# of electrons in an ion
# of protons +/- charge #
Z-effective
- effective nuclear charge - charge of an electron increases from left to right across a given period. ex. 2p orbital of a nitrogen atom experiences a greater z effect than a 2p orbital of a carbon atom - most effective when comparing electrons in the same shell and subshell for 2 different atoms.
Electron affinity
- energy change when an atom gains an electron - measured in kJ - alkaline earth metals and noble gases are happy with their full orbitals, they do not want to lose or gain any electrons - increased negativity to top right
ionization energy
- energy required to remove an atom - measured in kJ - As radius decreases across a period, the electron you are removing is closer to the nucleus and harder to remove. - outer electrons are farther from nucleus and easier to remove - inversely proportional with atomic radius - increases from bottom to top, and left to right - top right corner will have highest IE
valence electron configuration
- exists in S and P orbitals only! - outer shell electrons
electronegativity
- in general metals are e- givers and have low electronegativities. - nonmetals are electron takers and have high electronegativities - tend to increase across a period and decrease down a group
structure of an atom
- nucleus of an atom contains protons and neutrons - electrons of an atom are located outside of the nucleus - the number of protons of an atom defines the identity of an element - the mass of an atom is determined by the number of protons and neutrons it contains
octet rule exception
1) odd # valence electrons 2) reduced octect (H, Be, B) 3) Expanded octect (go beyond 8e-, beyond 3p orbitals)
homogenous
A mixture, solid, liquid, or gas that contains two or more substances blended evenly throughout. Ex. Just the salt water
formal charge
Charge assigned to an atom in a molecule or polyatmic ion, calculated by (# valence electrons) - (# 1/2 bonding electrons) - (# nonbonding electrons). Molecules containing atoms with lower formal charges tend to be more stable than those with higher formal charges.
paired electrons
DIAMAGNETIC two electrons together in an electron shell
groups and bonding
Group 4A= 4 bonds and 0lp Group 5A= 3 bonds and 1lp Group 6A= 2 bonds and 2lp Group 7A= 1bond and 0 lp
bond angles
NO2- < NO2 < NO2+
unpaired electrons
PARAMAGNETIC single valence electrons that are used for sharing with one another atom in a covalent bond. compare to lone pair 2 unpaired electrons = 1 paired electron
visible light
R-O-Y-G-B-I-V Red= 750nm - Violet= 400nm
to memorize order of waves
Rachel's mom is very large under x-rays gosh
sigma and pi bonds
Single bond has one σ bond. Double bond has one σ bond and one π bond. Triple bond has one σ bond and two π bonds. - sigma bonds include ALL bonds - pi bonds only include double and triple bonds, triple bonds make up two pi bonds.
max # of electrons that can occupy any orbital
TWO
covalent bond
a chemical bond that involves sharing a pair of electrons between atoms in a molecule
pure substance
a sample of matter, either a single element or a single compound, that has definite chemical and physical properties Ex. distilled water, Sodium
Resonance structure
a structure that occurs when it is possible to draw two or more valid electron dot structures that have the same number of electron pairs for a molecule or ion
largest emission of energy levels
anything that decreases to n= 1 n=5 - n=1 > n= 4 - n=1 > n=3 - n= 1 > n=2 - n=1
# of neutrons
atomic mass - # of protons
bond angles of water
closest to 105 degrees
Octet rule exceptions
dont need to fill all 8 valence electrons (octect) - Hydrogen = 2 electrons - Beryllium (Be) = 4 electrons - Boron (B) = 6 electrons
non-polar
even distribution of charge, equal pull
atomic structure periodic trend
every time we move up one group farther to the right, we add one more proton to the nucleus. (the actual nuclear charge, Z, increases by one) and we add one more electron to the valence shell.
hybridization
formation of 4 equivalent, single, covalent bonds
Ionic bond
formed between one element with a high electron affinity and another element with low ionization energy
polar
having a pair of equal and opposite charges; being pulled in different directions
Atomic Radius
increases from right to left and top to bottom bottom left will have greatest atomic radius - z-eff increases across a period
a single photon of light has the least amount of energy in the case of
infrared radiation
AB2
linear 0 lp linear molecular sp 180 ex. BeH2
heterogeneous
localized regions with different properties Ex. a combination of sand, salt, and water - sand on beach and bottom of ocean floor; salt mixed in with the water-you can't see if but you can taste it
metals, nonmetals, metalloids
metals= left side of the periodic table nonmetals= top right side of periodic table metalloids= stair step starting at B of group 3A B - si- ge/as -sb/te - At
quantum numbers
n = ___ l = n-1 ml = [-n...0...+n] ms = +/- .5
valence electrons
number corresponding to group number
AB6
octahedral octahedral molecular zero lone pair 90;180
AB5U
octahedral square pyramidal molecular 1 lone pair 90; 180
AB4U2
octahedral two lp square planar molecular 90; 180 sp3d2
Intensive property
properties not related to size or amount ex. Density
precision of a measurement
proximity of a measured number to other measured values not accurate, but consistent
accuracy of a measurement
proximity of a measured number to the TRUE value met goal but not consistent
extensive property
related to size or amount Ex. Mass
isotopic
same element; # of protons different # of neutrons
isoelectronic
same number of electrons
to show that a solid substance may contain an ionic bond
show it conducts electricity in aqueous solution
orbital shapes
spherical= S-block Dumbbell shaped= P-block Toroidal = D-block Flower= F-block
Isomere
strength increases as we get shorter = same formula different structure
AB2U2
tetrahedral bent/angular molecular geo two lone pairs sp3 < 109
AB3U
tetrahedral one lone pair trigonal pyramidal molecular sp3 < 109
AB4
tetrahedral zero lone pair tetrahedral molecular sp3 109.4
Lewis formation
the ion exists only in one form; an average of the principal structure
ion is drawn three different ways...
the ion exists only in one form; an average of the shown structures. an extra set of electrons changes the bond order around. extra bond is drawing o bond closer and stronger. bond order= #bonds/#connections
Ag vs. Ag1+
the ion has a higher effective nuclear charge, Zeff, than the atom
# of electrons
the same as the number of protons IF it is neutral; anions - add that number to the proton # cations - subtract that number from proton #
AB2U3
trigonal bipyramidal linear molecular 3 lone pair 180
AB3U2
trigonal bipyramidal t shaped molecular 2 lp 90; 180
AB5
trigonal bipyramidal trigonal pipyramidal molecular 0 lp 90;120;180
AB2U
trigonal planar one lone pair bent molecular
AB3
trigonal planar zero lone pair trigonal planar molecular sp2 120 ex. BF3
AB4U
triognal bipyramidal molecular see-saw one lp 90;120;180
bond length
triple bonds= shortest double bonds= longest
Waves
wavelength increases to the left energy increases to the right frequency increases to the right radio - microwave - infrared- visible light - UV light - x-rays - gamma rays