Lecture 4: Inorganic Chemistry PDF

-Covalent bond, polar covalent bond, Lewis structures, formal charges. -VSEPR Theory (valence shell electron pair repulsion theory ) Geometry of molecules....

-Covalent bond, polar covalent bond, Lewis structures, formal charges. -VSEPR Theory (valence shell electron pair repulsion theory ) Geometry of molecules. - Hybridization Lesson-4 Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA  Use Electronegativity Values to Determine Bond Types -Ionic bond Electronegativity (EN) difference > 2.0 How did we get here? -Polar Covalent bonds EN difference is between 2.1 and 1.99 -Non-Polar Covalent bonds EN difference is < 2.0 Electrons shared evenly in the bond Inorganic Chemistry-Ph.D.C E.HOXHA 5 Ionic Bonding Always formed between metal cations and non-metals anions The oppositely charged ions stick like magnets + - [METALS ] [NON-METALS ] Gained Lost e- e- Ionic bonding is between metals and non-metals e.g. sodium chloride, magnesium oxide. Neutral atoms come near each other. Electron(s) are transferred from the Metal atom to the Non-metal atom. They stick together because of electrostatic forces, like magnets. Inorganic Chemistry-Ph.D.C E.HOXHA 6 Covalent Bonding Pairs of e- are shared between 2 non-metal atoms to acquire the electron configuration of a noble gas. Occurs between nonmetal atoms which need to gain electrons to get a stable octet of electrons or a filled outer shell. The atoms form a covalent bond by sharing their valence electrons to get a stable octet of electrons. (filled valence shell of 8 electrons) Electron-Dot Diagrams of the atoms are combined to show the covalent bonds Covalently bonded atoms form MOLECULES Inorganic Chemistry-Ph.D.C E.HOXHA  Water is a POLAR molecule ANY time there are unshared pairs of electrons on the central atom, the molecule is POLAR H H O Inorganic Chemistry-Ph.D.C E.HOXHA 8 Making sense of the polar non-polar thing BONDS MOLECULES Non-polar Non-polar Polar Polar Symmetrical Asymmetrical EN difference EN OR difference Unshared e-s on 0-2 2.1 – 1.99 Central Atom Inorganic Chemistry-Ph.D.C E.HOXHA 9 Polar Molecules Molecule is Not Equal on all sides ○ Not a symmetrical shape of molecule (atoms surrounding central atom are not the same on all sides) Cl H C H H Inorganic Chemistry-Ph.D.C E.HOXHA 10 Nonpolar Molecules Molecule is Equal on all sides ○ Symmetrical shape of molecule (atoms surrounding central atom are the same on all sides) H Draw Lewis dot first and see if equal on all H C H sides Inorganic Chemistry-Ph.D.C E.HOXHA H 11 Polar Molecule δ+ H Cl δ- Unequal Sharing of Electrons Inorganic Chemistry-Ph.D.C E.HOXHA 12 Non-Polar Molecule Cl Cl Equal Sharing of Electrons Inorganic Chemistry-Ph.D.C E.HOXHA 13 Polar Molecule H Cl B H Not symmetrical Inorganic Chemistry-Ph.D.C E.HOXHA 14 Non-Polar Molecule H H B HSymmetrical Inorganic Chemistry-Ph.D.C E.HOXHA 15 VSEPR – Valence Shell Electron Pair Repulsion Theory Covalent molecules assume geometry that minimizes repulsion among electrons in valence shell of atom Shape of a molecule can be predicted from its Lewis Structure Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA  Linear 2 atoms attached to center atom 0 unshared pairs (lone pairs) Bond angle = 180o Type: AB2 Ex. : BeF2 Inorganic Chemistry-Ph.D.C E.HOXHA  Trigonal Planar 3 atoms attached to center atom 0 lone pairs Bond angle = 120o Type: AB3 Ex. : AlF3 Inorganic Chemistry-Ph.D.C E.HOXHA  Tetrahedral 4 atoms attached to center atom 0 lone pairs Bond angle = 109.5o Type: AB4 Ex. : CH4 Inorganic Chemistry-Ph.D.C E.HOXHA  Trigonal Bipyramidal 5 atoms attached to center atom 0 lone pairs Bond angle = ○ equatorial -> 120o ○ axial -> 90o Type: AB5 Ex. : PF5 Inorganic Chemistry-Ph.D.C E.HOXHA  Octahedral 6 atoms attached to center atom 0 lone pairs Bond angle = 90o Type: AB6 Ex. : SF6 Inorganic Chemistry-Ph.D.C E.HOXHA  Bent 2 atoms attached to center atom 2 lone pairs Bond angle = 104.5o Type: AB2E2 Ex. : H2O Inorganic Chemistry-Ph.D.C E.HOXHA  Trigonal Pyramidal 3 atoms attached to center atom 1 lone pair Bond angle = 107o Type: AB3E Ex. : NH3 Inorganic Chemistry-Ph.D.C E.HOXHA  A structure in which the formal charges are as close to zero as possible is preferred. Resonance occurs in cases where two or more Lewis structures with identical arrangements of atoms but different distributions of electrons can be written. Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA https://general.chemistrysteps.com/hybridization-of-atomic-orbitals/ Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA Inorganic Chemistry-Ph.D.C E.HOXHA  THANK YOU!! Inorganic Chemistry-Ph.D.C E.HOXHA