Chemical Bonds and Compounds 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. 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.
Transcript
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
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-
2
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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)
