Chem Grade 11 Exam Notes

Chem 11 Study Guide SCH3U
Unit 1
Definitions:
* SATP: Standard Ambient Temperature and Pressure ( 100kpa and 25 degrees C) * STP: Standard Temperature and Pressure (101.325kp and 0 deg C) * IUPAC: Intn’l Union of Pure and Applied Chem (approves, makes chem names symbols, etc. * Representative Elements: an element in any of groups 1,2,13-18 * Transition Metal: element of groups 3-12 * Energy level: a space with definite and fixed energy in which an electron is allowed to move * Orbit: circular/spherical path in which the electron can move around the nucleus * Electron Cloud: the region of an atom in which there is a probability that an electron exists * Quantum Mechanics: theory of the atom in which electrons are described in terms of their energies/probability patterns (model looks like smoke around a circle) * Principal Quantum # (n from 2n^2 formula for max # e- per level): # specifying the theoretical energy lvl of an elctron in the atom * Avg Atomic Mass: weighted avg of masses of an atom’s isotopes * Isotope: atoms with same # of protons but diff # of neutrons * Isotopic Abundance: % of an isotope in a sample of an element * Nuclear Charge: positive charge on nucleus (# of protons/atomic number) * Position of Outermost Orbital: dist. Btwn nucleus and valence e- (increases down cuz more lvls outweigh nuc charge, decreases across cuz same # o lvls, more nuc charge pulls elecs in) * Shielding Effect: extent to which elecs in inner orbits affect bonding of valence elecs * Atomic radius: size o atom (picometrs) (increases down cuz more levels outweigh nuc charge, increases to the left cuz of less nuc charge for same number of lvls) * Ionic Radius: radius as an atom becomes an ion (decreases since an element has one fewer energy level as it becomes a positive ion loses electrons) *increases downwards cuz more energy lvls to begin with even after losing, *increases to theleft cuz of less nuclear charge yet same number of lvls * Ionization Energy: amount of energy it takes to remove an electron from atom/ion in gas state (1st ~ = farthest elec, 2nd ~ = 2nd farthest, etc.) (increases upwards (requires more energy/is harder) cuz less lvls, less shielding effect = does NOT stop nuc charge making it harder and increases to right cuz more nuc charge, no increase in lvls= shielding effect = electrons pulled closer and made HARDER to remove) * Electronegativity: number that describe the relative ability of an atom when bonded to attract electrons (increases upwards cuz less shielding effect and increases to right cuz less shielding effect) * Electron Affiniy: the enrgy change that occurs when an electron is accepted by an atom in the gaseous state (same as ionization energy!) * Reactivity: how reactive the element is (metals = increases down and to left cuz shielding elec block nuc charge making elecs easier to remove so closer to losing enough to get an empty valence shell. Nonmetals = increases up cuz less nuclear charge, increases to right cuz more elecs but no increase in shielding effect so closer to achieving full valence shell) * Intramolecular Forces: the attractive forces between atoms and ions WITHIN a compound * Intermolecular forces: the attractive forces BETWEEN molecules * Ionic Compounds Properties: high melting point, solids at SATP, electrolyte, strong bond (crystal lattice) * Covalent Compounds Properites: low melting point, liquid/gas at SATP, don’t conduct/form electrolytes, flexible * Excited State: any state other than ground state * Ground State: lowest allowed energy state of an atom/molecule/ion * Catalyst: substance that speeds up the rate of a reaction without undergoing permanent change itself (does not get consumed/changed)
Notes:
* Diagnostic test for an ionic compound: check if it dissolves and becomes an electrolyte * Anything above and below any horizontal line segment of staircase is metalloid except obvious Aluminum * VSEPR Theory (Valence Shell Electron Pair Repulsion Theory):
REMEMBER THE FOLLOWING RULES: * Electron pairs repel one another and molecules will adjust their shape so that the electron pairs are as far apart as possible * **Electron pairs around the CENTRAL ATOM ONLY (both bonded and lone) influence the molecular shape! So rmr this one in particular! If it’s not near the central, it’s NOT counted!!!** * Lone pairs and bonded repel each other and themselves
SHAPES FOR VSEPR * Tetrahedral: 4 bond sites, 0 lone pairs, 109 degree angle, i.e. CH4 --- = behind --- = sticking out each line in general tho is a bond site * Trigonal Pyramidal: 3 bs, 1 lp, 107 degree angle, i.e. NH3 ..= lone pair * Bent: 2 bs, 2lp, 105 degree angle i.e. H2O * Linear: 2 bs 0 lp, 180 deg angle, i.e. NO2 **A double bond, triple bond etc. is STILL ONLY ONE BOND SITE!!!** * Trigonal Planar: 3bs, 0 lp,120deg angle i.e.CO3 * ****: any diatomic molecules = linear * ****: if more than one central atom, predict shape at each central atom SEPERATELY! * POLAR BONDS: * Using electronegativity number and VSEPR theory, you can figure out if a molecule is polar covalent, non-polar covalent, or ionic. * If the difference in elec-ity is