General Chemistry MCAT Memorization CHAPTER 1 Atoms Molecules and Quantum Mechanics Elementary Particles o A Elemental Descriptions o A Isotopes Nuclide o A Two or more atoms of the same element with different numbers of neutrons o B Same number of electrons o A Atom of a specific isotope Atomic Mass W eight amu or Molar Mass MM o A Carbon 12 has a mass of 12 amu s o A 6 022 x 1023 amu 1 gram o B Moles grams atomic or molecular weight o A Horizontal row in the periodic table of elements Groups Families o A Vertical columns in the period table of elements o B Atoms tend to make similar bonds and ions Moles Period Metals o A Tend to form positive ions o B Form ionic oxides i e BaO o C Characteristics 1 Luster 2 Ductile 3 Malleable 4 Thermal conductor 5 Electrical conductor Nonmetals o A Lower melting points than metals o B Form negative ions o C Comprise most molecular substances o D Form covalent oxides i e SiO2 Metalloids o A Some characteristics of metals and nonmetals Alkali Metals Group 1A o A First family o B Soft low density and melting point 1 1 o C Form 1 cations o D VERY reactive o E React with nonmetals to form ionic compounds o F React with hydrogen to form hydrides Alkaline Earth Metals Group 2A o A Second family o B Hard higher density and melting point than alkali metals o C Form 2 cations o D Less reactive than alkali metals o E Within the family reactivity heavier lighter Group 4A Carbon and Shit o A Form 4 covalent bonds with nonmetals o B Only carbon makes triple bonds within this family Group 5A Nitrogen and Shit o A Form 3 covalent bonds o B Except for Nitrogen all can form 5 covalent bonds d orbitals o C With a Lewis base can make 6 bonds Chalcogens Group 6A oxides i e KO2 Halogens Group 7A o A Oxygen reacts with metals to form oxides i e BaO o B Oxygen reacts with alkali metals to form peroxides i e Na2O2 and super o A Seventh family my own interpretation o B Most are diatomic o C Like to gain electrons o D All react with hydrogen to form gaseous halides Noble Rare Inert Gases o A Eighth Family my own interpretation o B Nonreactive o C All gases at room temperature o D Unlike all other elements they have endothermic electron affinity values Main Group Representative Elements o A Section A metals Transition Metals o A Section B metals o B When forming ions lose electrons from s subshell first and then d subshell and thus can form multiple ions e g Vanadium V o C Form colored solutions a result of partially filled d orbitals these electrons can absorb photons and be bumped up to a higher energy orbital Diatomics o A Oxygen o B Hydrogen o C Nitrogen o D Halogens o E Heat of Formation Small atoms Cations Anions o A Tend to be smaller o A Tend to be larger Isoelectric ions 1 The first three and fluorine from the Halogens all have an enthalpy change of zero o A Tend to be more reactive because they can t stabilize charge o A Same number of ions different protons o B Get smaller with increasing atomic number more protons to pull in electrons 2 2 3 Density etc matter Periodic Trends o A The alkali metals have lower density than the alkaline Earth metals as discussed above o B In a given sample of elements the gaseous element will have the smallest density density mass volume o C When comparing gases atomic weight and elemental form single diatomic Triatomic o A Decrease across Period Increase down Group Max Value Bottom Left 1 Atomic Radii 2 Ionic Radii 3 Energy of Valence Electrons 4 Metallic Character o B Increase across Period decrease down Group Max Value Top Right Atomic Radii 1 Effective Nuclear Charge Z 2 Electronegativity X 3 Ionization Energies increasingly endothermic 4 Electron Affinity increasingly exothermic o 1 Because size gets larger down and to the left and smaller up and to the right atoms most similar in size will be down and to the right or up and to the left o 2 Ex Phosphorous is most similar in size to Selenium Effective Nuclear Charge Z eff o A Because inner electrons shield outer electrons from full force of protons o A The tendency of an atom to attract electrons in a bond that it shares with another Electronegativity atom Ionization Energy Electron Affinity o B Measured in elements partaking in chemical bonds with other elements o A Energy necessary to detach an electron from a nucleus in its gaseous state o A Willingness of an atom to accept an additional electron i e the energy released when an electron is added to a gaseous atom o B Values for noble gases are endothermic Bohr s Equation for the Frequency of transmitted light when an electron falls from one orbital of a hydrogen atom to a lower one o 1 E A 1 ni 2 1 nf 2 o 2 Where A energy needed to remove an electron from the ground state of a hydrogen atom to an infinite distance from the atom Covalent Bond Bond length o A Two electrons are shared by two nuclei o A Inversely proportional with bond energy which is the energy needed to break a bond o B Inversely proportional with bond strength Bond dissociation bond energy o A Energy needed to completely separate two atoms Bond Types Compound 3 o A Two or more elements in whole number ratios Molecules o A The repeating groups of atoms in compounds o B Ionic compounds do not have molecules Empirical formula Molecular Formula Ionic compounds o A Simplest whole number ratio of atoms in a compound o A Representative of all the elemental atoms in a molecule o A Named after their cation or anion e g Copper II ion o B Monatomic anions ide e g Hydroxide o C Polyatomic ions ite or ate e g NO2 nitrite and NO3 nitrate Molecular Compounds o A Two nonmetals o B Always has covalent bonds Acids o A If name ends in ide it starts with hydro and ends in ic e g Hydrosulfuric acid o B If an oxyacid more oxygens ic and less oxygens ous Binary molecular compounds o A Compounds with only two elements o B Name begins with element farthest left and down may get prefix o C Second element gets the ide o D Ex Dinitrogen Tetroxide N2O4 Physical Reaction o A Maintains the molecular structure o B Ex melting evaporation dissolution rotation of light Chemical Reaction o A Molecular structure changes o B Ex Combustion metathesis redox Run to completion o A Moves to the right until the supply of at least one reactant is gone o B Reactions often don t do this because they reach equilibrium first Limiting Reagent o A Runs out and fucks everybody o B Ex …