Presentation on theme: "Chemical Bonding. Chemical Bond: attractive force between atoms or ions that binds them together as a unit atoms form bonds in order to… decrease potential."— Presentation transcript:
Chemical Bond: attractive force between atoms or ions that binds them together as a unit atoms form bonds in order to… decrease potential energy (PE) increase stability
Covalent bonding — electrons are shared between atoms in a molecule or in polyatomic ions Ionic bonding — positively and negatively charged ions are held together by electrostatic forces electrons are transferred
Polar Covalent: An unequal attraction for shared electrons creating partially charged poles- asymmetrical electron density Non-polar: electrons are shared equally- symmetrical electron density δ - symbol for partially negative δ + symbol for partially positive Two Types of Covalent Bonds
For Polar Covalent Bonds: higher electronegative atom = - lower electronegative atom = + Recall: Electronegativity is the measure of an atom’s ability to attract electrons! Determining Type of Bond Using Electronegativity Difference
For Ionic Bonds: The higher electronegative atom forms an anion. (gains electrons) The lower electronegative atom forms a cation. (loses electrons)
Determining Type of Bond Using Electronegativity Difference
Electronegativity Trend Increases up and to the right.
Ionic Polar-covalent Nonpolar-covalent 3.3 1.7 0.3 0 Difference in electronegativities The difference in electronegativity (END) determines bond type.
Use electronegativity values to classify bonding between: Sulfur (S) and Hydrogen (H) Cesium (Cs) and Fluorine (F) Chlorine (Cl) and Phosphorus (P) Practice
Bonding ENDBond type More negative atom S and H2.5 – 2.1 = 0.4polar-covalentsulfur Cs and F4.0 – 0.8 = 3.2ionicfluorine Cl and P3.0 – 2.2 = 0.8polar-covalentchlorine O and O3.5 – 3.5 = 0.0nonpolar-covalentNA Practice Solution
2s 2p2p 1s 2s 1s LiF + - How Does Bonding Work? Ionic Bond is then formed between F - & Li + e - transfer
2s 1s F How Does Bonding Work? Nonpolar Covalent Bond is then formed- F 2 shared e - (overlapping p orbital) 2p2p2p2p 1s 2s F
1s O How Does Bonding Work? Polar Covalent Bond is then formed. Oxygen is more electronegative than hydrogen- creating a polar molecule H 2 O. shared e - (overlapping s & p orbitals) 2p2p 1s H H δ-δ- δ+δ+ δ+δ+
Wrapping it Up! Nonpolar Covalent Bond electrons are shared equally symmetrical electron density usually identical atoms
Polar Covalent Bond electrons are shared unequally asymmetrical electron density results in partial charges Wrapping it Up!
Ionic Bond electrons are transferred ions are formed electrostatic attraction between cations and anions
Nonpolar Polar Ionic
Ionic – transfer of electrons (Metal + Non-metal) Did you notice this? More Wrapping it Up! Covalent – sharing of electrons (Non-metal + Non-metal) Did you notice this? Non-polar Polar