CHAPTER 7 CHEMICAL FORMULAS AND BONDING Date _____________ COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Ionic compounds (Elemental) Composition _____________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ metal + nonmetal (EN relatively large) sodium chloride NaCl copper sulfate Cu(SO4) chalcocite CuS calcium oxide CaO potassium nitrate K(NO3)

electrons are transferred Ionic compounds – Sodium Chloride as an example 11Na ____________________ 17Cl ________________________ Na Cl EN(Na) = _____ EN(Cl) = _____ 11Na+ ____________________ 17Cl- ________________________ electron configuration 1s22s22p63s1 1s22s22p63s23p5 electron dot diagram 1.0 3.0 enough atoms transfer enough electrons so that each resulting ion ends up with a full outer shell (FOS) (or full / ½-full sublevels or close…) electrons are transferred (from the metal atom to the nonmetal atom) electron configuration 1s22s22p6 1s22s22p63s23p6 - + electron dot (aka Lewis dot diagram structure)

+1 -1 1s22s22p6 1s22s22p63s23p6 - attract ionic bond 11Na+ ____________________ 17Cl- ________________________ Na Cl 1s22s22p6 1s22s22p63s23p6 + - e- e- e- e- inner shell (core) electrons e- e- e- 10e- 2e- e- +17 +11 e- outer shell electrons e- e- e- e- e- e- e- represents ____________ ____________ a sphere of +1 charge +1 represents ____________ ____________ a sphere of -1 charge -1 e- +17 e- +11 attract ionic bond

Cl- Cl- Na+ Na+ Na Cl Na Cl In a typical chunk (crystal) of sodium chloride, (say the size that comes out of your salt shaker - 1mm3), there would be ~21019 ions of sodium and of chlorine (20,000,000,000,000,000,000 or 20 billion billion) Okay, well…. What if there were 2 atoms each of sodium and chlorine ? Na Cl Na Cl Cl- Cl- Na+ Na+ bond bond too! bond remember, ions are spheres of charge… there’s no side of the ion that is more positive or negative than the other side…. (and the charges do not go away when the ions bond) so, one side of each ion is just as “sticky” as the other… so…

Cl- Cl- Cl- Cl- Cl- Na+ Na+ Na+ Na+ Na+ Na Cl Na Cl Na Cl Na Cl Na Cl What if there were 5 atoms each of sodium and chlorine ? Na Cl Na Cl Na Cl Na Cl Na Cl Cl- Cl- Na+ Na+ bond bond bond bond bond bond bond Cl- Cl- Na+ Na+ bond bond bond bond bond Cl- Na+ bond

Cl- Cl- Na+ Na+ Na Cl but… to give no one… it to hey I’ve got an electron to give…. but… me too… no one… me too… to give it to What if there were 5 atoms of sodium and 2 atoms of chlorine Na Cl Cl- Cl- Na+ Na+ bond bond bond

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Ionic compounds (Elemental) Composition _____________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ metal + nonmetal (EN relatively large) electrons transferred from metal atom to nonmetal atom, until one of them (metal or nonmetal or both) runs out forms cations (+) and anions (-) attract (bond) sodium chloride NaCl copper sulfate Cu(SO4) chalcocite CuS calcium oxide CaO potassium nitrate K(NO3)

Cl- Cl- Na+ Na+ Na Cl Na Cl In a typical chunk (crystal) of sodium chloride, (say the size that comes out of your salt shaker - 1mm3), there would be ~21019 ions of sodium and of chlorine (20,000,000,000,000,000,000 or 20 billion billion) Okay, well…. What if there were 2 atoms each of sodium and chlorine ? Na Cl Na Cl Cl- Cl- Na+ Na+ bond bond too! bond remember, ions are spheres of charge… there’s no side of the ion that is more positive or negative than the other side…. (and the charges do not go away when the ions bond) so, one side of each ion is just as “sticky” as the other… so…

Cl- Cl- Cl- Cl- Cl- Na+ Na+ Na+ Na+ Na+ Na Cl Na Cl Na Cl Na Cl Na Cl What if there were 5 atoms each of sodium and chlorine ? Na Cl Na Cl Na Cl Na Cl Na Cl Cl- Cl- Na+ Na+ cations bond to anions bond to cations bond to anions bond to anions…. until the ions run out bond bond bond bond bond bond bond Cl- Cl- Na+ Na+ bond bond bond bond bond how many atoms of each element there are to start with determines how many ions are bonded together in the “chunk” Cl- Na+ bond

cations bond to anions bond to cations bond to anions bond to anions…. until there are no more ions how many atoms of each element there are to start with determines how many ions are bonded together in the “chunk” so,….. no two “chunks” of sodium chloride will necessarily have the same number of ions of each element ________________________________ what is the same between each stable chunk ? ***KEY*** the total charge from all the cations must _______________________________________________________________ in a stable “chunk” equal the total charge from all the anions to be neutral / stable

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Ionic compounds (Elemental) Composition _____________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ metal + nonmetal (EN relatively large) electrons transferred from metal atom to nonmetal atom, until one of them (metal or nonmetal or both) runs out forms cations (+) and anions (-) attract (bond) cations bond to anions bond to cations bond to anions sodium chloride NaCl copper sulfate Cu(SO4) bond to cations bond to …. until they run out AND the structure is neutral chalcocite CuS calcium oxide CaO potassium nitrate K(NO3)

general definition Chemical Formula of a substance (any substance) represents : _____________________________________________ chemical formula for sodium chloride (ionic compound) for 1 atom each of sodium and chlorine _________________ for 2 atoms each of sodium and chlorine _________________ for 5 atoms each of sodium and chlorine _________________ for 6,667,000 atoms of each… __________________________ which is correct ? __________________ what is constant (the same) between them ? ______________ which is used ? ___________________ why ? ________________________ so, the chemical formula for ionic compounds is written as : _________________________________________________ called : ________________________________ the types of elements in the substance AND the number of atoms/ions of each in a piece of the substance Na+1Cl-1 Na+2Cl-2 Na+5Cl-5 Na+6,667,000Cl-6,667,000 they all are the ratio of Na+ to Cl- Na+1Cl-1 the simplest (the smallest whole number ratio) the smallest whole number ratio of ions of the elements in a stable (neutral) unit of the substance a formula unit

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Ionic compounds (Elemental) Composition _____________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ metal + nonmetal (EN relatively large) copper sulfate Cu(SO4) electrons transferred from metal atom to nonmetal atom, until one of them (metal or nonmetal or both) runs out sodium chloride NaCl forms cations (+) and anions (-) attract (bond) cations bond to anions bond to cations bond to anions bond to cations bond to …. until one runs out AND the structure is neutral the smallest whole number ratio of ions of the elements in a stable (neutral) unit of the substance (the stable unit is called a formula unit) chalcocite CuS calcium oxide CaO potassium nitrate K(NO3)

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Covalent compounds fluorine F2 water H2O carbon dioxide CO2 nitrogen N2 oxygen O2 DNA C1000’sH1000’sN1000’sO1000’sP1000’s isopropanol C3H8O polyacrylic acid (C3H4O2)n crude oil CxHy proteins – ex: collagen C5978H9285N1835O1941S31 vitamin C C6H8O6 fats C~40H~100O3

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Covalent compounds (Elemental) Composition ______________________________________ ___________________________________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ (EN relatively small) nonmetal + nonmetal OR metal + metal OR metalloid + any

- + H O H EN not equal H O H so, 1s22s22p4 1s1 1s1 Covalent compounds – Water as an example 8O ____________________ 1H ___________ “wants” ________ has ______ so, need __________ H O H EN(O) = _____ EN(H) = _____ H O H EN not equal H O H so, electrons shared ______________ _______ has _________________ covalent bonding : _________________________________________________ _________________________________________________ 1s22s22p4 1s1 1H ___________ 1s1 2e- 1e- another H atom electrons are shared in pairs 1 shared pair = 1 covalent bond 3.5 2.1 electrons shared (higher probability of the shared electrons being on/at the oxygen atom) - + a bigger share not equally O

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Covalent compounds (Elemental) Composition ______________________________________ ___________________________________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ (EN relatively small) nonmetal + nonmetal OR metal + metal OR metalloid + any enough atoms share enough electrons so that each has the equivalent of a full outer shell NO ions form / the stable unit is neutral

- + + - - + + - H H H H H O H H O H H O H H O H H O H bond ? What if there were 2 atoms of O and 4 atoms of H …. 3 atoms of O and 6 atoms of H …. 4 atoms of O and 12 atoms of H ….. the is a discrete, stable unit of water called a _____________________ ________________ do NOT _____________________________________ H H H H - + H O H - + for nonmetals bonding to nonmetals - + H O H - + H O H H O H bond ? bond ? are the + and - negative and positive enough to form a bond ? the answer is ________ NO (stick yes, bond no) H O H molecule molecules chemically bond to other molecules

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Covalent compounds (Elemental) Composition ______________________________________ ___________________________________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ (EN relatively small) nonmetal + nonmetal OR metal + metal OR metalloid + any enough atoms share enough electrons so that each has the equivalent of a full outer shell for nonmetals bonding to nonmetals form molecules fixed number of atoms of each element do not (chemically) bond to other molecules

- + - + - + H O H H O H H O H Chemical formula for molecular substances What is characteristic of molecules of substances ? so, the chemical formula will represent _______________________________________________________ the number of atoms of each element in a molecule ( a stable unit of the substance) H O H - + H O H - + H O H - +

COMPOSITION, BONDING, STRUCTURE, and CHEMICAL FORMULAS for Ionic and Covalent compounds Covalent compounds (Elemental) Composition ______________________________________ ___________________________________________________________ Bonding __________________________________________________ _________________________________________________________ Structure _________________________________________________ Chemical Formula _________________________________________ (EN relatively small) nonmetal + nonmetal OR metal + metal OR metalloid + any enough atoms share enough electrons so that each has the equivalent of a full outer shell for nonmetals bonding to nonmetals form molecules fixed number of atoms of each element do not (chemically) bond to other molecules the number of atoms of each element in a molecule (stable unit) of the substance

GUMDROPS