Entire Chem 1A Lecture/Textbook Notes.doc

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Department
Chemistry
Course
CHEM 1A
Professor
Nien-hui Ge
Semester
Spring

Description
Week 1 • atomic radius - 100 pm (pico meter) or 1 x 10^-10 m • nuclear radius - 5 x 10^-3 pm or 5 x 10^-15 m • • periodic table o atomic number - number of protons o mass number - number of protons + neutrons o element symbol • Definitions o macroscopic - visual observation (ex. looking at rust) o microscopic - looking at the chemical makeup (ex. molecules that makeup rust) o molecule: aggregate of 2 or more atoms held by chemical forces o diatomic molecule - contains 2 atoms o polyatomic ion - covalently bonded elements w/a charge: OH- o ion - atom or group of atoms with a + or - charge o cation - +, loses electron o anion - -, gains elctrons o isotopes - same atom with different neutrons. same chemical properties, different physical properties • chemical formulas o molecular formula - actual # of atoms o empirical formula - ratio # of atoms • Ionic Compound o consists of combination of cations and anions o no molecular formula, only empirical because they cant exist alone (ex. NaCl) o sum of cation and anion charges in each formula need to = 0 • Mass o amu - atomic mass unit  1.066054 x 10^-27 o Carbon is the 'standard  weighs 12 amu exactly o Mass Spectrometer  measures an atom's amu  light atoms bend more, heavy atoms bend less o the mole  1 mole of anything = 6.022*10^23 units of that thing  6.022*10^23 molecules/1 mole  molar mass = how many grams are in 1 mole (g/mol)  water has 18g/mol  moles = ions/A# • naming compounds o Ionic  name of cation (+, usually metal) then the root of the anion (-, usually nonmental) +ide  NaCl - sodium chloride o Covalent (molecular)  prefix (if nonmetal) + full name of more metallic (left side)  prefix (if nonmetal) + root of less metallic + ide (right side) o acid  has an H  HCl - hydrochloric acid  if there is an O at the end drop the hydro and dont say a thing about the O (sometimes)  HNO - nitric acid • Element that comes first in a molecular formula - most electropositve o bottom left to top right • Greek Prefixes Number mono- 1 di- 2 tri- 3 tetra- 4 penta- 5 hexa- 6 hepta- 7 octa- 8 nona- 9 deca- 10 • • tera 10^12 • giga 10^9 • mega 10^6 • kilo 10^3 • hecto 100 • deca 10 • deci .1 • centi .01 • mili 10^-3 • micro 10^-6 • nano 10^-9 • pico 10^-12 • Text Symbol Factor tera T 1000000000000 giga G 1000000000 mega M 1000000 kilo k 1000 hecto h 100 (none) (none) 1 deci d 0.1 centi c 0.01 milli m 0.001 micro μ 0.000001 nano n 0.000000001 • 1 m^3 = 1000 liters • Week 2/3 • law of conversion of mass • atoms can't be created or destroyed • wavelength (λ) • distance between identical points • distance/wave • units: m, um (10^-6m), nm (10^-9m), Å (10^-10m) • amplitude • vertical distance from the midline to peak/trough • frequency (v) • # of waves that passes a point in 1sec • #of waves/time • units: cycles/s, 1/s, s^-1, hertz, Hz • speed (u) • distance/time • units: m/s, nm/s • Maxwell (1873) proposed that visible light consists of electromagnetic waves • electromagnetic radiation - emission and transmission of electromagnetic waves • visible light spectrum: 4 x 10^-7 ~ 7 x 10^-7 • light • speed of light (c) 3 x 10^8 m/s • light has both wave and particle nature • photon is a particle of light • Planck's quantum theory - theory of black body radiation • energy (light) is emitted and absorbed in discrete units (quantum) • quantum - smallest energy that can be emitted or absorbed in the form of EM waves o when change of Energy is +, absorbed o when change of Energy is -, emitted • equations • J = Kg m^2/s^2 • u = λv o speed = (wavelength)(frequency) • v = c/λ o frequency = (speed of light)/(wavelength) • E = hv = mc^2 o energy(photon) = (6.62608 *10^-34Js)(frequency) = (mass of photon) (speed of light)^2 o total energy(J) = (#of photons)(energy of photons) o frequency rises, energy of photons rise o wavelength rises, energy of photons decrease • kE = (1/2)mv^2 o Kinetic energy = (1/2)(mass Kg)(velocity^2) • Bλ = h/mv o de Broglie's wavelength m = (6.62608*10^-34Js)/((mass Kg)(velocity m/s)) • En=-R HZ /n ) o change in energy = - (2.178*10^-18J)((nuclear charge)^2/ (quantum number)^2) o delta E = Einitial - Efinal • f = c/λ o (Threshold Frequency) = (speed of light)/(Threshold wavelength) • kE = E - Hf o Kinetic Energy = Energy - (6.62608 *10^-34Js)(Threshold Frequency) • Week 4/5/6 • light is emitted when e- moves to lower energy levels • LASER - light amplification by stimulated emission of radiation • an electron bound to the nucleus behaves like a standing wave o o o node-^ (has amp 0) • Heisenberg uncertainty principle - cant determine position and velocity simultaneously o p = mv  momentum = mass(velocity) o ▲X▲P > h/4pi  change in position and momentum > (6.62608 *10^-34Js)/(4pi) • electron density - probability that an e- will be found in a particular region • Quantum Numbers Name Symbol Values Specifies Indicates Principle n 1, 2, infin Shell Size Angular l 0,1,2,..n-1 Subshell Shape momentum s,p,d,f,g,h… Magnetic m l 0, +/-1,…+/- l Orbitals of Orientation subshells Spin ms +1/2^, +1/2v Spin state Spin oreintation • l = 1 (p orbitals) ml = -1, 0, +1 • l = 2 (d orbitals) ml = -2, -1, 0, 1, 2 • spin o • • order of orbitals o 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s • rules for assigning e- o Aufbau principle - electrons are added to an atom starting at the lowest energy level first o Hund's Rules - electrons fill all available orbitals before pairing up  degenerate - same energy level o Pauli exclusion principle - maximum of 2 electrons in a single orbital • some names o paramagnetic - unpaired electrons  ^ ^ o diamagnetic - all electrons are paired  ^v ^v • exceptions! o Cr: [Ar] 4s1_3d5 o Cu: [Ar] 4s1_3d10 • Valence Electrons o inner (core) - all inner e- o outer - e- in the highest energy levels (highest n) o valence - e- involved in bonding  column # for representative elements (1A-7A) o transition metals lose their s electron before their d  s is farther from nucleolus then d • electron configuration - how e-s fit into the orbitals • isoelectronic - 2 elements have same makeup o [Ne] and Na+ • oxidation state - charge on the ion (for monoatomic ions) • Effective nuclear charge (Zeff) - positive charge felt by an e- o smallest on top left, biggest bottom right o shielding e-'s - the non-valence electrons which shield the nucleus' charge (elements w/the same n have the same shielding constant) • atomic radius - 1/2 the distance between 2 nucleus' o biggest bottom left, smallest top right (opposite of IE, EA, and EN) • ionization energy (IE) - min energy in kJ/mol required to remove an e- (in gasses) o smallest bottom left biggest top right (1st ionization energy) o x(g) -> x+(g) + e-(g) ▲E=I1 1stionization energy o x+(g) -> x2+(g) + e-(g) ▲E=I1 2nd ionization energy • Electron affinity - negative energy charge when an e- is accepted by an atom to form an anion o same as ionization energy, except halogens have the highest EA o ▲E = -EA • Electronegativity (EN) - the ability of an atom to attract towards itself the electrons in a chemical bond o smallest bo
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