Chemical Bonds and Compounds Standards 3b:Students know that compounds are formed by combining two or more different elements and that compounds have properties.

Chemical Bonds and CompoundsStandards 3b:Students know that compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent, original, elements. Standards 3c:Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.Standards 3f:Students know how to use the Periodic Table to identify elements in simple compounds.Standards 7c:Students know substances can be classified by their properties, including their melting temperature, density, hardness, and thermal and electrical conductivity.

3 Types of Chemical bonds•Covalent▫Co = with▫sharing

•Ionic ▫Gain e- negative charge▫Lose e- positive charge

•Metallic▫Free flow e-

Standards 3b:Students know that compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent, original, elements.

•Bond – attractive F bwtn atoms▫Valence e- allow bonds

•Element order important▫CO2 is different from CO

•Form new substance▫Properties, traits, characteristics different ▫C-solid + O-gas- CO (poisonous gas)

Ratio of atoms important•Compounds written as chemical formula

▫Subscripts state number of atoms and cannot b

Standards 3b:Students know that compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent, original, elements.

•Molecule vs. Compound•Molecule- two or more atoms

▫Ex.- O2 N2 H2

•Compound- two or more elements▫Ex.- CO, CO2 , H2O, C2H5OH

•Bonds depend on valence e-

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Covalent Bonds•Nonpolar

▫e- = shared btwn atom

•Polar▫e- ≠ shared btwn

atoms▫Btwn non-metals▫Shape refers to

imbalance n bond

Covalent Bonds

•Bonds ▫Single- share valence e- with one other atom▫Double- share two valence e- w/ one atom▫Triple- share three valence e- w/ one atom

Covalent Bonds:Standards 3c:Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.

•C forms many different bonds•Form long chains or branches of long

chains•Polymers

Metallic Bonds•Arrangement of e- allows metal to bend/malleable

•Many e- shared•Free flowing of e-

•E- change position easily

Ionic BondsTraits

Ions bond to form salt• Give up or accept e-• Bonds btwn metals n

nonmetal • Need valence e- to fill

outer energy lvl• Position e- determines

bond• Creates crystal lattice-salt• Anion- gain e- ( affinity)

▫ Nonmetals (Grp 16, 17)• Cation-lose e- (ionization)

▫ Metals (Grp 1, 2)• Attraction btwn opposite

charges

Ionic Compounds

•Bonds pull on each other from opposite charges

•+ and – pull on each other in all directions•Form crystals•Repeat pattern

Standards 3f:Students know how to use the Periodic Table to identify elements in simple compounds.

Standards 3f:Students know how to use the Periodic Table to identify elements in simple compounds.