Chemical Bonds All atoms seek a state of balance - a full outer shell of electrons Number of electrons in the outer orbit (shell) gives the element its chemical & physical properties All atoms want to have an electron structure of a noble (inert) gas

Chemical Bonds Therefore: a chemical bond is produced Atoms bond together to form a compound Compound - a combination of elements Compounds can be a solid, liquid, or a gas

Chemical Bonds Molecule Result of a chemical bond Smallest particle with its unique identity Water - H2O Air – O2 N - 78% O - 21% Ar - 1%

Chemical Bonds Valence electrons Chemical Bonds Electrons located in the outer orbit (shell) Participate in chemical bonding Inner orbits are stable Chemical Bonds A process of transfer, (giving/receiving) or sharing of electrons in order to reach a stable state 3 types Ionic bonds Covalent bonds Metallic bonds

Chemical Bonds Ionic bond Electrons are transferred (received or given-up) + or - ion is formed Metal from the left side of the PT reacts with a nonmetal from the right side of the PT Sodium Chloride - NaCl - table salt Sodium - left - 1 electron to give Chlorine - right - needs 1 electron

Chemical Bonds Covalent Bonds Electrons are shared Nothing given or received Form between the nonmetallic elements (right)

Chemical Bonds Examples of Covalent bonds Hydrogen Chloride Methane HCl Hydrogen Chloride CH4 Methane H2O Water SiO2 Quartz CCl4 Carbon tetrachloride CO Carbon monoxide C6H12O6 Glucose

Chemical Bonds Metallic bonds Electrons are shared

Chemical Bonds Ionic Bond vs Covalent Bond Ionic bonds Covalent bond Electrons are transferred Form between metals & nonmetals Metals – left side of PT Nonmetals – right side of PT Covalent bond Electrons are shared Forms between nonmetals

Chemical Bonds Electronegativity An atom’s pulling ability Difference in the electronegativity will determine the bond type Fig. 9.10 (p. 259)

Chemical Bonds Compound Names ide suffix - compound contains 2 elements