BONDING

CONDUCTIVITY The ability of a substance to conduct electricity SOLUBILITY The ability of a substance to dissolve in a liquid (mostly water) Lab Review

VOLATILITY The ability of a substance to turn into a gas (or vaporize) MELTING TIME The time it takes for a solid to turn into a liquid Lab Review

Bond vs. Compound COMPOUND –two or more elements chemically combined –the substance BOND –the link between elements –what holds the substance together An ionic compound has ionic bonds.

Bond vs. Compound

Why do atoms bond? To achieve the octet rule  in order to have 8 valence electrons having 8 valence electrons makes them stable or “happy”

What are valence electrons? EXACTLY!EXACTLY! valence electrons are the electrons found in the outermost shell of an atom

Do you remember this? VALENCE ELECTRONS Group 1 Group 2 Group 13 Group 14 Group 15 Group 16 Group 17 Group

Any guess as to what the other electrons are called? core electrons yep!yep!

types of bonds Ionic Covalent Metallic

IONIC BONDS bond between a metal and a nonmetal to achieve octet for both atoms (e.g. NaCl) involves transfer of electrons

IONIC BONDS one atom gains electrons (ANION); the other atom loses electrons (CATION) attraction between oppositely charged ions holds ions together (EMF)

IONIC COMPOUNDS ions are arranged so that… –like charges are far from each other –opposite charges are close WHY? –because opposites attract –like charges repel

CRYSTAL LATTICE Red spheres represent Cl -1 Yellow spheres represent Na +1 NaCl (table salt) link to table salt crystal

IONIC COMPOUNDS high MP/BP since lots of energy is needed to overcome the lattice arrangement gives ionic compounds stability –Low volatility high solubility in water high conductivity lattice arrangement gives specific shape to crystals of compound

COVALENT BONDS bond between 2 nonmetals to achieve octet sharing of valence electrons

COVALENT BONDS Between 2 nonmetals so…. –both attract e- attraction between nucleus and shared e- holds atoms together usually between atoms w/ high ionization energies and high e- affinities

COVALENT COMPOUNDS Two nonmetals make a molecule –combination of atoms formed by covalent bond –ex: CO 2

COVALENT COMPOUNDS usually low MP/BP b/c attraction between molecules weak only small amount of energy needed to separate molecules from one another –high volatility do not easily dissolve in water low conductivity

NETWORK SOLIDS exception to low MP b/c atoms continue to bond together; get huge molecules e.g. graphite, diamond, glues

METALLIC BONDS between 2 metals positive nuclei of atoms surrounded by free-moving electrons all electrons attracted by all the nuclei at the same time

METALLIC BONDS »common distribution of electrons throughout metallic crystals WHY? –metals give up electrons easily –low ionization energy & low electron affinity

METALLIC SOLIDS sea of electrons accounts for metallic properties: –malleability –ductility –high conductivity –high melting point/boiling point