CFE (LEC) FINALS PDF

COES110A COVALENT BOND FORMATION...

COES110A COVALENT BOND FORMATION - Increase negative charge between two CHEMISTRY FOR ENGINEER LECTURE. —---------------------------—---------------------------—----------------—---------------------------—---------------------------—----------------—---------------------------—---------------------------—------------------------ positive - Link between atom (sharing of two electrons) -LESSON 3 CLASSIFICATION OF MATTER----- - ELEMENT MOLECULE - Can’t be converted into simpler Substances - Uncharged collection of atom (Smallest substances) - Compare molecules with 2 hydrogen NONPOLAR COVALENT BOND - If the electrons are shared equally, there is an COMPOUND even distribution of the negative charge. - There are no partial charges on the atoms. - Two or more elements - H2O, NaCI - Contain 1 oxygen atom and 2 hydrogen (Combining whole number ratio) MIXTURES POLAR COVALENT BOND - Combination of two or more substances (elements and compound) - Bond attracts electrons more than the other - Variable composition atom. + Sugar dissolved in water - The other atom loses negative charge giving it a partial positive HETEROGENEOUS MIXTURES - Different parts and composition HOMOGENEOUS MIXTURES IONIC BOND - Mixed down to molecular level - The attraction between cation and anion - Forming a positively charged particle or cation to the nonmetallic atom forming a negatively PURE SUBSTANCES charged particle or anion. - Constant composition that can be described with chemical formula + Copper, Cu, and compounds, glucose --------COMPOUNDS AND CHEMICAL BONDING—----- TYPES OF COMPOUND PARTICLES AND WAVE NATURE MOLECULAR COMPOUND - Both particle and wave character - All nonmetallic atoms usually lead to all - Less massive the particle covalent bonds. - The electron has low mass, low enough to IONIC COMPOUNDS significant - Metal-nonmetal combinations usually lead to ionic bonds. —----------MOLECULAR COMPOUNDS—------------ BONDING FOR HYDROGEN MOLECULAR COMPOUNDS - Hydrogen has only one electron, so they form one covalent bond. - All nonmetallic usually leads to all covalent - When a hydrogen atom forms a bond to bonds chlorine atom, they form hydrogen chloride, HCI. VALENCE ELECTRONS - Each atom are the most important electrons in the formation of chemical bonds VALENCE ELECTRONS AND A-GROUP ELEMENTS - Number of the atoms of each element is equal to the elements A-group ELECTRON-DOT SYMBOLS - Show valence electrons - the pair of valence electrons called Ione pairs. OCTETS OF ELECTRONS - Very stable noble gas atoms other than helium have 8 valence electrons. BONDING FOR THE HALOGENS - All halogens in group 7A have seven valence electrons FORMATION OF Cl2 - Each chlorine atom has one unpaired valence - Form one covalent bond and have three lone electron pair. - The unpaired electrons from the two chlorine atoms pair up to form a covalent bond - Octet of eight electrons BONDING FOR OXYGEN, SULFUR, & SELENIUM - O,S, and Se are in group 6A, so their atoms have 6 valence electrons. LEWIS STRUCTURE - Represent molecules using element symbols, - Form two covalent bonds and have two lone lines for bonds, and dots for lone pairs. pairs. BONDING FOR NITROGEN AND PHOSPHORUS —------------------- ---EXAMPLE—--—------------------- - Nitrogen and phosphorus in group 5A have 5 valence electrons PH3 - Form three covalent bonds and have one lone pair. HOCI CCI3F BONDING FOR CARBON - Carbon is in 4A, so it has four valence electrons C2H2 - Form 4 covalent bonds and no Ione pair. CH4 NH3 MOST COMMON BONDING PATTERNS FOR NONMETALS H2O ------BINARY COVALENT NOMENCLATURE—----- COMMON NAMES H2O WATER NH3 AMMONIA CH4 METHANE DOUBLE BONDS C2H6 ETHANE - Atoms can share four electrons. - Two lines in Lewis structures. + Carbon dioxide CO2 C3H8 PROPANE C4H10 BUTANE TRIPLE BONDS C5H12 PENTANE - Atoms can share six electrons HEXANE - Three lines in Lewis structures. C6H14 + Nitrogen N2  —-------—------IONIC COMPOUNDS—---- ----------- PREFIXES SUMMARY MON(O) HEX(A) Atoms of metallic elements - Weak electron attraction DI HEPT(A) Atoms of nonmetallic elements - Strong electron attraction TRI OCT(A) Metallic + non metallic = Ionic bond Anion - nonmetallic form anions → gain TETR(A) NON(A) enough electrons to gen same no. of electrons PENT(A) DEC(A) + Ex. oxygen has 6 valence - Meaning: it needs 2 more for the octet rule NAMING BINARY COVALENT COMPOUNDS - How: Look at the nearest noble gas, for oxygen, it is 10 (Neon) so gain 2 more electron N2O3 Dinitrogen trioxide - Answer: O2- N2O5 Dinitrogen Pentoxide Cation - opposite → instead of negative, use positive NO2 Nitrogen Dioxide + Ex. aluminum - Answer: Al3+ NO Nitrogen Monoxide NAMING MONATOMIC ROOTS OF EXAMPLES ELEMENTS CATION (naming of metal)(Roman numeral) + Example: Gold(III) H hydr- ➔ br2O7 = ANION C carb- N nitr- dibromine (root of nonmetal name)ide + Example: flourIDE, ioIDE, hydrIDE O ox- heptoxide Monatomic anions only has 11 elements, they S sulf- Se selen- ➔ PCl3 = are all nonmetals. F fluor- phosphorus Cl chlor- trichloride Br brom- POLYATOMIC ION I iod- ➔ CO = carbon A charged collection of atoms held together monoxide by covalent bonds ➔ H2S = dihydrogen monosulfide ➔ N2O4 = dinitrogen tetroxide ➔ PBr3 = phosphorus POLYATOMIC IONS WITH HYDROGEN tribromide - Put H in front. ➔ HI = hydrogen iodide  CoCl2 CONVERTING IONIC NAMES TO FORMULA SUMMARY TABLE OF CATIONS NH4NO3 EXAMPLE OF CATION IDENTIFYING NAMES AS IONIC COMPOUNDS SUMMARY TABLE OF ANIONS EXAMPLE FOR ANION WRITING IONIC FORMULAS Determine the formula, including charge, for MgO the cation and anion. Determine the ratio of the ions that yields zero overall charge CONVERTING IONIC NAMES TO FORMULAS Dito yung part na hindi naglalagay ng charges. Pagpapalitan ng charges ng compound and ilalagay siya as subscript