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FORCES BETWEEN PARTICLES

FORCES BETWEEN PARTICLES. NOBLE GAS CONFIGURATIONS. PERIOD GROUP. El Camino College Chemistry 21A Dr. Dragan Marinkovic. FORCES BETWEEN PARTICLES. NOBLE GAS CONFIGURATIONS.

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FORCES BETWEEN PARTICLES

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  1. FORCES BETWEEN PARTICLES NOBLE GAS CONFIGURATIONS PERIOD GROUP El Camino College Chemistry 21A Dr. Dragan Marinkovic

  2. FORCES BETWEEN PARTICLES NOBLE GAS CONFIGURATIONS PERIOD GROUP Rn 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s24f14 5d10 6p6 1s2 2s2 2p6 3s2 3p6 4s23d10 4p6 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s24d10 5p6 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 1s2 2 8 8 8 8 8 VALENCE SHELL ELECTRONS NOBLE GASES = INERT GASES El Camino College Chemistry 21A Dr. Dragan Marinkovic

  3. FORCES BETWEEN PARTICLES NOBLE GAS CONFIGURATIONS 1s2 2s2 2p6 1s 1s2 1s2 2s 1s2 2s2 2p3 1s2 2s2 2p4 1s2 2s2 2p 1s2 2s2 2p2 1s2 2s2 2p5 1s2 2s2 Lewis structures of the elements in the first two periods. usually 8 = OCTET RULE : atoms will gain or lose sufficient electrons to achieve an outer electron arrangement identical to that of a noble gas. By G. N. Lewis and Walter Kossel Predicts electron behavior in reacting atoms. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  4. FORCES BETWEEN PARTICLES IONIC BONDING, IONIC COMPOUNDS During some chemical interactions the OCTET RULE is satisfied when electrons are transferred from one atom to another. Na Na+ + e- Cl + e- Cl- Na + Cl Na+Cl- Mg Mg2+ + 2e- O + 2e- O2- Mg + O Mg2+O2- SIMPLE ION :an atom that acquired a net positive or negative charge by losing or gaining electrons. Ca Ca2+ + 2e- 2F + 2e- 2F- Ca + 2F Ca2+F2- IONIC BOND :the attractive force that holds together ions of opposite charge. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  5. FORCES BETWEEN PARTICLES IONIC BONDING; IONIC COMPOUNDS Mg Mg2+ + 2e- O + 2e- O2- Mg + O Mg2+O2- Ca Ca2+ + 2e- 2F + 2e- 2F2- Ca + 2F Ca2+F2- IONIC COMPOUNDS Formulasrepresent the combining ratio of positive and negative ions found in compounds. This ratio is determined by the charges on the ions, which are determined by the number of electrons transferred. metals lose electrons GENERAL RULE during bond formation nonmetals gain electrons ISOELECTRONIC = “same electronic” (configuration) ISOELECTRONIC = same noble gas electronic configuration, but atoms DO NOT turn into the noble gases – they still have their unique number of protons and ONLY number of protons determines elements. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  6. FORCES BETWEEN PARTICLES IONIC BONDING; IONIC COMPOUNDS BINARY COMPOUNDS = compounds made up of two different elements. BINARY COMPOUND NAME = METAL + NONMETAL STEM + IDE. nonmetal atom stem carbon carb- nitrogen nitr- phosphorus phosph- arsenic arsen- oxygen ox- sulfur sulf- selenium selen- fluorine fluor- chlorine chlor- bromine brom- CuF CuF2 copper(I) fluoride copper(II) fluoride cuprous fluoride cupric fluoride FeCl2 FeCl3 iron(II) chloride iron(III) chloride ferrous chloride ferric chloride CoO Co2O3 cobalt blue cobalt(II) oxide cobalt(III) oxide cobaltous oxide cobaltic oxide mixed valence compound Co3O4 cobalt(II,III) oxide!!! (CoO·Co2O3) El Camino College Chemistry 21A Dr. Dragan Marinkovic

  7. FORCES BETWEEN PARTICLES IONIC BONDING MOLECULESare the smallest particle of pure substance that has properties of that substance and is capable of stable independent existence. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  8. FORCES BETWEEN PARTICLES IONIC BONDING MOLECULESare the smallest particle of pure substance that has properties of that substance and is capable of stable independent existence. Compound formulais a symbol for the molecule of a compound, consisting of the symbols of the atoms found in the molecule. Some compound formulasare used to represent a single molecule. Molecular formulasrepresent the precise number of atoms of each element found in a molecule. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  9. FORCES BETWEEN PARTICLES IONIC BONDING MOLECULESare the smallest particle of pure substance that has properties of that substance and is capable of stable independent existence. Compound formulais a symbol for the molecule of a compound, consisting of the symbols of the atoms found in the molecule. Some compound formulasare used to represent a single molecule. Molecular formulasrepresent the precise number of atoms of each element found in a molecule. Formulasof ionic compounds represent only a simplest combining ratio of the ions in the compounds. A stable form of an ionic compound is not a molecule, but a CRYSTAL in which many ions of opposite charge occupy LATTICE SITES in a rigid three dimensional arrangement called a CRYSTAL LATTICE. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  10. FORCES BETWEEN PARTICLES IONIC BONDING Rigid three dimensional arrangement is called a CRYSTAL LATTICE. NaCl Na Na+ + e- Cl + e- Cl- Na + Cl Na+Cl- CuF2 El Camino College Chemistry 21A Dr. Dragan Marinkovic

  11. FORCES BETWEEN PARTICLES IONIC BONDING Formulasof ionic compounds represent only a simplest combining ratio of the ions in the compounds. However,formulas are still used, especially in equations representing chemical reactions, or when theMOLEconcept is applied in chemical formulas. Na + Cl Na+Cl- 23.0 + 35.5 = 58.5 When theATOMIC WEIGHTSmaking up a true molecular formula are added together, the result is the MOLECULAR WEIGHTof the compound. For the ionic compounds we call itFORMULA WEIGHT. The termFORMULA WEIGHTcan be used for bothionic compounds and molecular compounds. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  12. FORCES BETWEEN PARTICLES COVALENT BONDING Achemical bondis a strong attraction between two or moreatoms. Bonds hold atoms in molecules and crystals together. There are many typesof chemical bonds, but all involve electronswhich are either shared or transferred between the bondedatoms. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  13. FORCES BETWEEN PARTICLES COVALENT BONDING Achemical bondis a strong attraction between two or moreatoms. Bonds hold atoms in molecules and crystals together. There are many types of chemical bonds, but all involve electrons which are either shared or transferred between the bonded atoms. It is known that the stable form of gases, like oxygen, nitrogen and chlorine are diatomic molecules O2, N2and Cl2. Obviously, such molecular bonds cannot be formed by electron transfer from one atom to another like in ionic molecules. G. W. Lewis proposed that in these molecules VALENCE SHELL ELECTRONS ARE SHARED in order to satisfy the OCTET RULE for EACH of the ATOMS. Such BONDSare calledCOVALENT BONDS. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  14. FORCES BETWEEN PARTICLES COVALENT BONDING Noble gas configuration (in this case, that of neon, s2p6) is achieved when two fluorine atoms (s2p5) are able to share an electron pair, which becomes the covalent bond. Notice that only the outer (valence shell) electrons are involved. H· + H·    H:H or H-H El Camino College Chemistry 21A Dr. Dragan Marinkovic

  15. FORCES BETWEEN PARTICLES COVALENT BONDING In the Electron Dot Notation, the dots represent electrons that are involved (or have the potential to be involved) in forming covalent bonds between atoms. Alternatively, each covalent bond (electron pair) may be represented by a solid line. DOUBLEandTRIPLE BONDS result from sharing two and three pairs of electrons, respectively. Ammonia, NH3 El Camino College Chemistry 21A Dr. Dragan Marinkovic

  16. FORCES BETWEEN PARTICLES POLYATOMIC IONS POLYATOMIC IONSare COVALENTLY BONDED GROUPS of atoms that carry a NET ELECTRICAL CHARGE. With the exception of NH4+, polyatomic ions are NEGATIVELY CHARGED. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  17. FORCES BETWEEN PARTICLES POLYATOMIC IONS phosphate El Camino College Chemistry 21A Dr. Dragan Marinkovic

  18. FORCES BETWEEN PARTICLES SHAPES OF MOLECULES AND POLYATOMIC IONS Most molecules and polyatomic ions do NOT have flat (planar, two-dimensional) shapes, but three dimensional shapes. The valence shell electron pair repulsion (VSEPR) modelfocuses on the bonding and nonbonding electron pairs present in the outermost (“valence”) shell of an atom that connects with two or more other atoms.Thecovalent model of chemical bonding assumes that the electron pairs responsible for bonding are concentrated into the region of apace between the bonded atoms. If the central atom also contains one or more pairs of nonbonding electrons, these additional regions of negative charge will behave very much like those associated with the bonded atoms. The orbitals containing the various bonding and nonbonding pairs in the valence shell will extend out from the central atom in directions that minimize their mutual repulsions. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  19. FORCES BETWEEN PARTICLES SHAPES OF MOLECULES AND POLYATOMIC IONS A simple triatomic molecule of the type AX2 has its two bonding orbitals 180° apart, producing a molecule that we describe as having linear geometry. In an AX3 molecule such as BF3, there are three regions of electron density extending out from the central atom. The repulsion between these will be at a minimum when the angle between any two is (360° ÷ 3) = 120°. This requires that all four atoms be in the same plane; the resulting shape is called trigonal planar, or simply trigonal. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  20. FORCES BETWEEN PARTICLES SHAPES OF MOLECULES AND POLYATOMIC IONS Methane, CH4, contains a carbon atom bonded to four hydrogens. What bond angle would lead to the greatest possible separation between the electron clouds associated with these bonds? In analogy with the preceding two cases, where the bond angles were 360°/2=180° and 360°/3=120°, you might guess 360°/4=90°; if so, you would be wrong. The latter calculation would be correct if all the atoms were constrained to be in the same plane (we will see cases where this happens later), but here there is no such restriction. Consequently, the four equivalent bonds will point in four geometrically equivalent directions in three dimensions corresponding to the four corners of a tetrahedron centered on the carbon atom. The angle between any two bonds will be 109.5°. This is called tetrahedral coordination. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  21. FORCES BETWEEN PARTICLES SHAPES OF MOLECULES AND POLYATOMIC IONS SO42- PO43- El Camino College Chemistry 21A Dr. Dragan Marinkovic

  22. FORCES BETWEEN PARTICLES SHAPES OF MOLECULES AND POLYATOMIC IONS The water molecule ammonia El Camino College Chemistry 21A Dr. Dragan Marinkovic

  23. FORCES BETWEEN PARTICLES THE POLARITY OF COVALENT MOLECULES Cl2 (Cl-Cl) El Camino College Chemistry 21A Dr. Dragan Marinkovic

  24. FORCES BETWEEN PARTICLES THE POLARITY OF COVALENT MOLECULES δ- δ+ δ- andδ+ δ-Cl-Brδ+ Cl-Br Cl2 (Cl-Cl) El Camino College Chemistry 21A Dr. Dragan Marinkovic

  25. FORCES BETWEEN PARTICLES THE POLARITY OF COVALENT MOLECULES δ- δ+ δ- andδ+ δ-Cl-Brδ+ Cl-Br Cl2 (Cl-Cl) Theelectronegativity of an atom denotes its relative electron-attracting power in a chemical bond. The 0-4 electronegativity scale of Pauling An atom that has a small electronegativity is said to beelectropositive. The metallic elements are generally electropositive. Linus Carl Pauling (1901–1994) El Camino College Chemistry 21A Dr. Dragan Marinkovic

  26. FORCES BETWEEN PARTICLES THE POLARITY OF COVALENT MOLECULES δ- δ+ δ- andδ+ partial ionic character of covalent bond δ-Cl-Brδ+ Cl-Br Cl2 (Cl-Cl) bond polarization polar covalent bond polar covalent bond nonpolar covalent bond polar molecule polar molecule nonpolar molecule Using Electronegativity to Identify Ionic, Covalent, and Polar Covalent Compounds H2O O EN = 3.44 H EN = 2.20 ∆EN = 1.24 CH4SO2 C EN = 2.55   O EN = 3.44 H EN = 2.20   S EN = 2.58 ∆EN = 0.35 ∆EN = 0.86 NaClSrBr2 Cl EN = 3.16   Br EN = 2.96 Na EN = 0.93   Sr EN = 0.95 ∆EN = 2.23         ∆EN = 2.01 covalent compounds ionic compounds El Camino College Chemistry 21A Dr. Dragan Marinkovic

  27. FORCES BETWEEN PARTICLES ionic bond non-polarcovalent bond polar covalent bond El Camino College Chemistry 21A Dr. Dragan Marinkovic

  28. FORCES BETWEEN PARTICLES OTHER INTERPARTICLE FORCES Ionic and covalent bonding explains certain properties of substances. Some experimental observations can be explained only by proposing other types of forces between particles. Ionic compounds in solid state form crystal lattice. Actually, most pure substances (molecules or atoms) form crystal lattices in solid state. When heated, solids melt and forces holding particles in dense organized form weaken and particles move about more freely – in liquid state. More heating overcomes attractive interparticle forces even more turning the liquid into a gas or vapor (the liquid boils). Interparticle forces are minimal and particles move about freely – gas (vapor) state. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  29. FORCES BETWEEN PARTICLES OTHER INTERPARTICLE FORCES Melting and boiling points can give us indication of the strength of interparticle forces that are being overcome. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  30. FORCES BETWEEN PARTICLES OTHER INTERPARTICLE FORCES Melting and boiling points can give us indication of the strength of interparticle forces that are being overcome. METALLIC BOND Attraction between positively charged atomic kernels taht occupy lattice sites and mobile electrons that move freely through the lattice. • NETWORK SOLID • lattice sites are • occupied by atoms • covalently bonded. DIPOLAR FORCE the attractive force between the positive end of one polar molecule and the negative end of another. HYDROGEN BONDING attractive dipolar forces between molecules in which hydrogen atoms are covalently bonded to very electronegative elements (F, O, or N). El Camino College Chemistry 21A Dr. Dragan Marinkovic

  31. FORCES BETWEEN PARTICLES OTHER INTERPARTICLE FORCES HYDROGEN BONDING attractive dipolar forces between molecules in which hydrogen atoms are covalently bonded to very electronegative elements (F, O, or N). DIPOLAR FORCE the attractive force between the positive end of one polar molecule and the negative end of another. NO or CO ammonia hydrogen fluoride MOLECULES WITH HYDROGEN BONDS. water El Camino College Chemistry 21A Dr. Dragan Marinkovic

  32. FORCES BETWEEN PARTICLES OTHER INTERPARTICLE FORCES ‘UNIQUENESS OF WATER” Molecule b.p. (oC) H2O 100 H2S -60.3 H2Se -41.3 The strong hydrogen bonds orient H2O molecules into a very open 3-D crystal lattice when it freezes. The open lattice occupies more space than liquid. El Camino College Chemistry 21A Dr. Dragan Marinkovic

  33. FORCES BETWEEN PARTICLES OTHER INTERPARTICLE FORCES e.g. H2, F2, O2, N2 Dispersion forces veryweak attractive forces acting between particles of ALL matter. The result from momentary non-symmetric electron distributions in molecules or atoms. Relative strength of interparticle forces El Camino College Chemistry 21A Dr. Dragan Marinkovic

  34. FORCES BETWEEN PARTICLES NAMING OF COMPOUNDS Number Greek Latin ½ hemi- semi-/demi- 1 mono- uni- 1¼ quasqui- 1½ sesqui- 2 di- duo-/bi- 3 tri- tre-/ter- 4 tetra-/tetr- quadri-/quadr- 5 penta-/pent- quinque-/quinqu- 6 hexa-/hex- sexa-/sex- 7 hepta-/hept- septua- 8 octa-/octo-/oct- 9 ennea- nona-/non- 10 deka-/deca- deci- 11 hendeca- undec- 12 dodeca- duodec- 13 triskaideka- tridec- 14 tetradeca- quattuordec 15 pentadeca- quindec- 16 hexadeca- sedec- 20 icosa- vigen- 100 hecto-/hect- centi- 1000 chilia-/kilo- milli- 10000 myria- El Camino College Chemistry 21A Dr. Dragan Marinkovic

  35. FORCES BETWEEN PARTICLES NAMING OF COMPOUNDS Number Greek Latin ½ hemi- semi-/demi- 1 mono- uni- 1¼ quasqui- 1½ sesqui- 2 di- duo-/bi- 3 tri- tre-/ter- 4 tetra-/tetr- quadri-/quadr- 5 penta-/pent- quinque-/quinqu- 6 hexa-/hex- sexa-/sex- 7 hepta-/hept- septua- 8 octa-/octo-/oct- 9 ennea- nona-/non- 10 deka-/deca- deci- 11 hendeca- undec- 12 dodeca- duodec- 13 triskaideka- tridec- 14 tetradeca- quattuordec 15 pentadeca- quindec- 16 hexadeca- sedec- 20 icosa- vigen- 100 hecto-/hect- centi- 1000 chilia-/kilo- milli- 10000 myria- Examples: CrO3 chromium trioxide NaOH sodium hydroxide KMnO4 potassium permanganate OsO4 osmium tetroxide SF6 sulfur hexafluoride (NH4)2CrO4 (di)ammonium chromate Li3PO4 trilithium phosphate PCl5 phosphorus pentachloride El Camino College Chemistry 21A Dr. Dragan Marinkovic

  36. FORCES BETWEEN PARTICLES El Camino College Chemistry 21A Dr. Dragan Marinkovic

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