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CHEMICAL BONDS. How atoms combine to form different bonds How to predict what type of bond will form. Electrons are what cause atoms to “bond.” Two main types of bonding IONIC bonding : atoms transfer electrons COVALENT bonding : atoms share electrons. TYPES OF BONDS.
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CHEMICAL BONDS • How atoms combine to form different bonds • How to predict what type of bond will form
Electrons are what cause atoms to “bond.” Two main types of bonding • IONIC bonding: atoms transfer electrons • COVALENT bonding: atoms share electrons TYPES OF BONDS
Held by +/- attraction • Form ions (e- transfer) & conduct electricity • OPPOSITE sides of Periodic Table non-metal + metal IONIC BONDS
IONIC BONDING PRACTICE: draw the formation of sodium chloride • Step 1: Na + Cl Na + Cl • Step 2: draw dots around the reactants • Step 3: draw dots and charges around the products sodium gives e leaving it with a full valence orbital chlorine gains e- leaving it with a full valence orbital
PREDICTING IONIC BONDING • Opposite sides of PT (i.e. metal + non-metal) • Big difference in Electronegativity (≥ 1.8)
NAMING IONIC COMPOUNDS • Name of 1st element (metal) • Root of 2nd element (nonmetal) • Root + “-ide” MgOmagnesium + oxygen magnesium oxide LiFlithium + fluorine lithium fluoride
Held by sharing electrons(co=together valent=valence e-) • Does NOT conduct electricity • Usually same side of PT COVALENT BONDS non-metal + non-metal or metal + metal Special type of covalent is metal to metal = metallic bond
PREDICTING COVALENT BONDING • Same sides of PT (non-metal + non-metal) • Small difference in Electronegativity (< 1.8)
NAMING COVALENT COMPOUNDS • Same as ionic (add –ide) • Add prefixes: • First Word • 1 = (understood) • 2 = di • 3 = tri • 4 = tetra • 5 = penta • 6 = hexa • Second Word • 1 = mono • 2 = di • 3 = tri • 4 = tetra • 5 = penta • 6 = hexa
PRACTICE NAMING CO Carbon monoxide CO2 Carbon dioxide SO2 sulfur dioxide CCl4 Carbon tetrachloride H2O Dihydrogen monoxide Si5P4 Pentasilicon tetraphosphide
PREDICTING BONDS USING PT & ELECTRONEGATIVITY COVALENT BOND IONIC BOND How can you tell if a bond is ionic or covalent? • Opposite or same sides of PT (covalent = SAME) • ELECTRONEGATIVITY! (the ability to attract e-) Electronegativity difference≥1.8 = IONIC < 1.8 = COVALENT
Bonding practice: Na Cl 0.9 3.0 3.0 -.9 2.1 >1.8? Yes! IONIC Na Cl metal non-metal Opposite sides? Yes! IONIC
Bonding practice: C Cl non-metal non-metal Opposite side? No! COVALENT C Cl 2.5 3.0 3.0 -2.5 0.5 >1.8? No! COVALENT