Atomic'Structure'

Number'of'protons'in'the'nucleus'

Neutral'atoms'have'equal'numbers'of'protons'and'electrons.''The'electrons'can'occupy'only'specific'energy'levels,'and'each'energy'level'can'only'contain'a'set'number'of'electrons'(2'eF'in'E1,'8'eF'in'E2,'etc.)'''

Chemical'bond'

Chemical'bonds'result'from'any'redistribu4on'of'electrons'that'leads'to'a'more'stable'configura4on'between'two'or'more'atoms'

The'most'stable'configura4on'–>'''''''''''''''''''''''''''a'filled'electron'shell'

No'bonds'–'noble'gases'

Ionic'Bonds'

Chemical'bond'in'which'one'or'more'electrons'from'one'atom'are'removed'and'aOached'to'another'atom,'resul4ng'in'posi4ve'and'nega4ve'ions'which'aOract'each'other'

Ionic'Bonds'

Ionic'Bonds'and'Material'Proper4es'

Ions'typically'form'crystal'structures'that'are'strong'along'the'direc4on'of'the'bonds,'but'can'be'broken'easily'if'twisted'or'bent'

Ex:'rock,'china,'glass,'bones,''''''''''''''''''''''''''''''''''''''''''''egg'shells,'salt'

Metallic'Bond'

Chemical'bond'in'which'electrons'are'redistributed'so'that'they'are'shared'among'many'atoms'

Metallic'Bonds'and'Material'Proper4es'

Unlike'ionic'crystals,'metals'are'malleable'–'upon'applica4on'of'a'force,'atoms'can'rearrange'themselves'into'a'different'shape'

Covalent'Bond'

Chemical'bond'in'which'one'or'more'pairs'of'electrons'are'shared'by'two'atoms'

Covalent'Bond'

examples'

Covalent'Bonds'and'Material'Proper4es'

Atoms'in'covalent'materials'are'bound'4ghtly'to'each'other'in'stable'molecules,'but'those'molecules'are'generally'not'very'strongly'aOracted'to'other'molecules'in'the'material'

Covalent'Bonds'of'Carbon'

Carbon’s'outer'shell'contains'four'electrons'–>'can'form'covalent'bonds'with'up'to'four'atoms'

Covalent'Bonds'of'Carbon'buckyballs'

nanotube'

Organic'Chemistry'

a'protein'

'''''''''''''''''''''''DNA'

States'of'MaOer'

States'of'MaOer'

Solid'–'any'collec4on'of'atoms'or'molecules'that'maintains'a'fixed'shape'and'volume'

Liquid'–'any'collec4on'of'atoms'or'molecules'that'has'no'fixed'shape'but'maintains'its'volume'

Gas'–'any'collec4on'of'atoms'or'molecules'that'takes'the'shape'of'and'fills'the'volume'available'in'its'container'

States'of'MaOer'

Plasma'–'similar'to'a'gas,'but'the'electrons'are'stripped'from'their'atoms'

Types'of'Solids'

crystal'–'groups'of'atoms'occur'in'a'regularly'repea4ng'sequence'

glass'–'no'longFrange'order'to'the'atomic'structure'

polymer'–'long'and'large'molecules'made'up'of'smaller'molecules'in'a'regular'repea4ng'sequence'''

Material'Proper4es'F'Strength'

Strength'is'the'ability'of'a'solid'to'resist'changes'in'shape'

Strong'materials'require'strong'chemical'bonds'

Material'Proper4es'F'Strength'

Strength'is'the'ability'of'a'solid'to'resist'changes'in'shape'

Strong'materials'require'strong'chemical'bonds'Many'strong'materials'–'rocks,'glass,'ceramics'–'are'held'together'by'ionic'bonds'

Material'Proper4es'F'Strength'

Strength'is'the'ability'of'a'solid'to'resist'changes'in'shape'

Strong'materials'require'strong'chemical'bonds'The'strongest'materials'we'know'–'spider'webs,'Kevlar,'diamonds,'plas4cs,'etc.'–'contain'long'chains'and'clusters'of'carbon'atoms'held'together'by'covalent'bonds'

Kevlar'

aerogel'

Composite'Materials'

Combina4ons'of'two'or'more'materials,'typically'designed'so'the'strength'of'one'of'the'materials'offsets'a'weakness'of'another'

Examples:'

Composite'Materials'

Combina4ons'of'two'or'more'materials,'typically'designed'so'the'strength'of'one'of'the'materials'offsets'a'weakness'of'another'

Examples:'plywood,'reinforced'concrete,'car'windshield'

Electrical'Proper4es'of'Materials'

Electrical'Proper4es'of'Materials'

Conductor'–'any'material'capable'of'carrying'electrical'current'

Insulator'–'a'material'that'will'not'conduct'electricity'(unless'subjected'to'an'extremely'high'voltage)'

Conductors'

Insulators'

Electrical'Proper4es'of'Materials'

Conductor'–'any'material'capable'of'carrying'electrical'current'

Insulator'–'a'material'that'will'not'conduct'electricity'(unless'subjected'to'an'extremely'high'voltage)'

Superconductor'–'a'material'that'conducts'electricity'without'resistance'

Semiconductor'–'neither'a'good'conductor'nor'perfect'insulator'

Applica4ons'of'superconduc4vity'

SiliconFbased'Semiconductors'

Diodes'

A'combina4on'of'one'nFtype'semiconductor'and'one'pFtype'semiconductor''

It'allows'the'flow'of'current'in'only'one'direc4on'

Diodes'

A'combina4on'of'one'nFtype'semiconductor'and'one'pFtype'semiconductor''

It'allows'the'flow'of'current'in'only'one'direc4on'

Transistors'

A'combina4on'of'one'type'of'semiconductor'sandwiched'in'between'two'semiconductors'of'the'opposite'type'

p''''''''''''n''''''''''''''p' n'''''''''''''p''''''''''''''n'

Transistors'

A'combina4on'of'one'type'of'semiconductor'(base)'sandwiched'in'between'two'semiconductors'of'the'opposite'type'

A'small'amount'of'electrical'charge'run'into'or'out'of'the'base'can'change'the'electric'fields'at'each'junc4on,'thus'controlling'the'current'through'the'transistor'

Transistors'can'be'used'as'amplifiers'(cell'phone,'radio)'or'switches'(computers)'

n'''''''''''''p''''''''''''''n'