Presentation on theme: "The Nonmetal-Nonmetal vs Metal – Nonmetal Bond"— Presentation transcript:
1 The Nonmetal-Nonmetal vs Metal – Nonmetal Bond Covalent andIONIC BONDINGThe Nonmetal-Nonmetalvs Metal – Nonmetal Bond
2 Lewis Dot StructuresA famous chemist named Lewis invented a symbol to show valence electrons. He used a dot next to the symbol to represent each valence electron. The dots are spread around the 4 sides.Each pair of dotsRepresents a bond.
3 Covalent BondsWhat is a Covalent Bond?- A covalent bond is a chemical bond resulting from SHARING of electrons between 2 nonmetals.?
4 Covalent Bonds can have multiple bonds, so you should be familiar with the following… Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms. H2ODouble Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms. CO2Triple Covalent Bond-chemical bond resulting from sharing of three electron pairs between two atoms. N2
5 Types of Covalent Bonds Two types of colvalent bonds: nonpolar and polarRecall electronegativity (desire for electrons) -see shaded table on ole yellerThe electronegativity difference between the two atoms determines whether it is a nonpolar or polar bond.Electronegativity difference:Nonpolar Polar Ionic
6 Polar BondsA nonpolar bond tends to share electrons equally A polar bond means there is a dipole or one pole (end) with a positive charge and one pole (end) with a negative charge, therefore they tend to stick together better since their opposite charges attract. (=)(-) Very strong polar bonds are ionic bonds like NaCl
7 Covalent Bonds Do NOT have ions or need to Balance Charges They use prefixes to show the number of atoms:Mono-Di-Tri-Tetra-Examples:H2O =dihydrogen monoxideCO2 = carbon dioxidedinitrogen tetraoxide = N2O4Phosphorus trichloride = PCl3
10 When a metal and nonmetal come together, a pair of electrons acts as a bond and they each become ions.
11 Ionic Bonding Rules: Metal first, nonmetal second Nonmetal ion becomes ‘ide’Metal is positive, nonmetal is negativeCharges must balance to zeroFormula uses a subscript to balance chargesExample: MgCl2 ; Na2O; NaCl
12 The sodium atom and chloride atom bond together as ions and form a new compound.
14 Practice: Sodium and fluorine Barium and iodine lithium and phosphorus Aluminum and oxygenBeryllium and oxygenCalcium and nitrogen
15 lithium and phosphorus Answers:Sodium and fluorinesodium fluorideNaFBarium and iodinebarium iodideBaI2lithium and phosphoruslithium phosphideLi3PAluminum and oxygenaluminum oxideAl2O3Beryllium and sulfurberyllium sulfideBeSCalcium and nitrogencalcium nitrideCa3N2
16 SolutionsWhen ionic compounds are put in water, they dissolve into ions:
17 Polyatomic ions: are groups of atoms bonded together with a charge hence the name “poly” “atomic” “ions”.*They behavejust like single atomions.Examples:OH-1 = hydroxideNO3-1 = nitratePO4-3 = phosphateSO4-2 = sulfate
18 Practice: Use polyatomic ions just like any other ion; But when you have more than one , use parentheses.barium hydroxide=(Notice parentheses show multiple ions.)
26 Transition metals: Metals that have more than one possible charge: Cobalt: Co+2, Co+3Copper: Cu+, Cu+2Iron: Fe+2, Fe+3Lead: Pb+2, Pb+4When writing the names, always use roman numerals to show the charge.
27 Examples:Cobalt (II) Co+2, Cobalt (III) Co+3Copper(I), Cu+, or Copper (II), Cu+2Iron(II) Fe+2, or iron (III), Fe+3Lead(II), Pb+2, or lead (IV), Pb+4Each different charged ion behaves completely different than the other! The charges matter!
36 HydratesSome ionic compounds absorb water molecules into their structures. These are called hydrates. NaCl•2H2O is the symbol for sodium chloride dihydrate. Notice the prefix di- means 2 water molecules. Name these hydrates: MgSO4•5H2O CuCl2•4H2O
37 Finding Percentage of Water in a Hydrate You can find the percentage of water in a hydrate by dividing the mass of the water by the total mass times 100.Lets take NaCl•2H2OUsing the periodic table, the mass of Na=23, Cl=35.5, H2O = 18. Total mass with 2 H20 is 94.4Water mass (36)/ Total (94.4) x 100= 38 % water
38 What are the differences between ionic bonding and covalent bonding What are the differences between ionic bonding and covalent bonding? List them below:
39 Differences: Ionic Metal , nonmetal-ide Balance charges using subscriptsPolyatomic ions use parentheses in multiplesTransition metals use roman numerals to show charge
40 Differences: Covalent Two nonmetals Nonmetal, nonmetal-ide No ions- they share e-Use prefixesDon’t need to balance
41 Differences: Ionic Metal , nonmetal-ide Balance charges using subscriptsPolyatomic ions use parentheses in multiplesTransition metals use roman numerals to show chargeCovalentTwo nonmetalsNonmetal, nonmetal-ideNo ions- they share e-Use prefixesDon’t need to balance