sign in sign up
<<
Home , Chemical compound, Ionic compound

CHEMICAL COMPOUNDS - VOCABULARY

COVALENT COMPOUND A compound that has only covalent bonds between of which it is made. The results from sharing between two atoms. The representative unit of a covalent compound is usually a .

IONIC COMPOUND A compound that is built of monatomic or polyatomic of opposite charges. The bonds between ions of opposite charges are called ionic bonds. Many, but not all ionic compounds contain a metallic element. The representative unit of an is always a unit. There no in ionic compounds. Ions per se are not compounds.

FORMULA UNIT The smallest combination of atoms or ions that correctly represents the ratio in which they are combined in a . is a more general term than a molecule.

ORGANIC COMPOUND A compound that is built of atoms of and other elements (most commonly, , , , sulfur, and ) except for carbon monoxide, carbon dioxide, carbonic , , and hydrogen carbonates. If there is no carbon present, a compound is certainly inorganic. The simplest is CH4, methane.

BINARY COMPOUND Ionic or covalent compound that is made of atoms of two different elements. Examples: MgCl2; Al2O3; HCl; H2O; CH4.

DIATOMIC MOLECULE A molecule that is built of exactly two atoms either of the same element or of two different elements. Examples: O2; N2; CO; HF.

MONATOMIC A single that lost or gained one or more electrons as compared to the neutral atom of the same element. The electric charge must be indicted when a formula of it is written unless the ion is combined with another ion in the formula of an ionic compound. Examples: Na+; Fe3+; Br–; S2–.

POLYATOMIC ION A group of atoms either of the same element or different elements held together by covalent bonds like atoms in a molecule, but unlike a molecule carrying nonzero electric charge. per se is not a compound, but it can be part of an ionic compound when combined with an ion of opposite charge. The electric charge must be indicted when a formula of it is written unless the ion is combined with another ion in the formula of an ionic compound. + 2+ – 2– 2– Examples: NH4 ; Hg2 ; NO3 ; SO3 . (SO3 is not the same as SO3 .)

ACID A covalent compound whose molecules have a special that can be detached from the rest of the molecule as (H+) in an aqueous . The rest of the molecule becomes a negatively charged ion. A pure acid may not conduct , but its aqueous solution (acid mixed with ) does conduct electricity. The sour taste of is due to hydrogen ion. (solid, , )

Substances Physical (constant composition) Change (variable composition)

Organic Elementary Chemical Compounds Homogeneous Compounds Heterogeneous Substances Change Mixtures Mixtures Inorganic (or ) Compounds

Metals Metalloids Ionic Covalent Compounds Compounds

Representative Molecule Formula Unit Atom Atom Molecule Atom Formula Unit Particle

O2, O3, Cl2, SiO2(quartz), P4, S8 SiC SUMMARY OF SYSTEM SUBSTANCE NAME FORMULA OR ION Elementary Name of element Symbol of element; common exceptions: Substance H2, N2, O2, F2, Cl2, Br2, I2

Monatomic Cation Name of element followed by ion; if element Symbol of element followed by superscript forms more than one monatomic cation, to indicate charge elemental name is followed by ion charge in and in parentheses

Monatomic Anion Name of element changed to end in –ide Symbol of element followed by superscript followed by ion to indicate charge

Compounds made First element in formula followed by second, Symbol of first element in name followed up of atoms of two change to end in -ide; each element by symbol of second element, with nonmetals preceded by prefix to show the number of subscript to show number of atoms in the atoms in the molecule molecule

Acid Most common: middle element changed to H followed by symbol of followed end in -ic by O (if necessary), each with appropriate One more oxygen than -ic acid: add prefix subscript per- to name of -ic acid MEMORIZE THE FOLLOWING: One fewer oxygen than -ic acid: change Nitric acid: HNO3 ending of -ic acid to -ous : H2SO4 Two fewer than -ic acid: add prefix : H2CO3 hypo- to name of -ous acid Phosphoric acid: H3PO4 No oxygen: Prefix hydro- followed by name of Chloric acid: HClO3 second element changed to end in –ic Acetic acid: HC2H3O2

Polyatomic anion Replace -ic in acid name with -ate, or replace Acid formula without hydrogen plus from total -ous in acid name with -ite, followed by ion superscript showing negative charge equal ionization of to number of removed from oxyacid acid formula

Polyatomic anion Hydrogen followed by name of ion from total Acid formula minus one (or two for H3PO4) from step-by-step ionization of acid (dihydrogen in the case of hydrogen(s), plus superscript showing – ionization of H2PO4 ) negative charge equal to number of oxyacid hydrogen atoms removed from acid formula

+ Other polyatomic ion NH4 ions ion OH– 2+ (I) ion Hg2

Ionic Compound Name of cation followed by name of anion Formula of cation followed by formula of (omitting ion in each of the names) anion (usually no charges indicated), each taken as many times as necessary to yield a net charge of zero (polyatomic ion enclosed in parentheses if taken more than once)

Hydrated Name of anhydrous compound followed by Formula of anhydrous compound followed (number prefix), where (number by “∙X H2O” where X is the number of prefix) indicates the number of water water molecules associated with one molecules associated with one formula unit of formula unit of anhydrous compound anhydrous compound

Naming Inorganic Compounds

yes no (= ionic compound) or NH4? (= covalent compound)

yes Group I or II; no yes no H in front? Al, Ag, Zn, NH4?

yes O is present, no

but not H2O or H2O2? yes no (aq) is written?

Type I Ionic Type II Ionic Oxyacid Nonoxyacid Binary Covalent Compound Compound Compound

Al2O3 (s) CuCl(s) HClO(aq) HCl(aq) HCl(g) P2O5(s) aluminum copper(I) hypochlorous acid diphosphorus pentoxide

LiOH (s) CuCl2(s) HClO2(aq) H2S(aq) H2S(g) NO2(g) hydroxide copper(II) chloride hydrosulfuric acid

AgNO3(s) Fe2O3(s) HClO3(aq) HCN(aq) HCN(g) S2Cl2(l) silver nitrate iron(III) oxide chloric acid hydrocyanic acid hydrogen disulfur dichloride

Na2O2(s) FeO(s) HClO4(aq) or (l) CO(g) peroxide iron(II) oxide perchloric acid H2O2(l) carbon monoxide CaCO3(s) Cr2(SO4) 3(s) H2SO3(aq) PF5(g) chromium(III) H2O(l) phosphorus pentafluoride NH4NO3(s) MnS(s) H2SO4(aq) or (l) water XeF4(s) manganese(II) sulfide sulfuric acid tetrafluoride

Sn(NO3) 2(s) NH3(g) (II) nitrate

CH4(g) methane CHEMICAL SYMBOLS AND FORMULAS

Al 1) Element aluminum Example: Al is the third most abundant element in the Earth crust.

2) Elementary substance (aluminum metal) Example: 5.0 grams of Al.

3) One atom of aluminum

2Al Two (individual) atoms of aluminum

2H Two (individual) atoms of hydrogen

H2 1) Molecular hydrogen; substance (hydrogen gas) Example: A balloon is filled with H2 gas.

2) One molecule of hydrogen

H2O 1) Water as a substance (a covalent compound) Example: 50 mL of H2O.

2) One molecule of water

2H2O Two molecules of water

2Al + 3O2 Two atoms of aluminum mixed with three molecules of oxygen

Al2(SO4)3 1) Aluminum sulfate as a substance (an ionic compound) Example: 3.30 grams of Al2(SO4)3.

2) One formula unit of aluminum sulfate: each 2 atoms of aluminum chemically combined with 3 SO4 groups (atoms of aluminum, sulfur and oxygen chemically combined in the ratio of 2:3:12)

GREEK PREFIXES FOR NAMING COMPOUNDS

Number Prefix

1/2 hemi-

1 mono-

2 di- bicycle

3 tri- tricycle

4 tetra-

5 penta- the Pentagon

6 hexa-

7 hepta- September

8 octa- October

9 nona- (Latin) November

10 deca- December

11 undeca- (Latin)

12 dodeca-

13 trideca-

20 icosa-

Prefixes that are in bold should be memorized!!! NAMES AND FORMULAS OF COMMON IONS

POSITIVELY CHARGED IONS (CATIONS) NEGATIVELY CHARGED IONS (ANIONS) The charges of these ions can be figured out The charges of these ions can be figured out using the : using the periodic table: hydrogen ion H+ ion H– lithium ion Li+ ion F– sodium ion Na+ chloride ion Cl– ion K+ bromide ion Br– rubidium ion Rb+ iodide ion I– cesium ion Cs+ oxide ion O2– ion Be2+ sulfide ion S2– magnesium ion Mg2+ nitride ion N3– calcium ion Ca2+ phosphide ion P3– strontium ion Sr2+ barium ion Ba2+ aluminum ion Al3+

These ions must be memorized: These ions must be memorized: + – hydronium ion H3O acetate ion C2H3O2 + – ammonium ion NH4 hydroxide ion OH silver ion Ag+ cyanide ion CN– cadmium ion Cd2+ cyanate ion OCN– zinc ion Zn2+ thiocyanate ion SCN– + – copper (I) or cuprous ion Cu ion ClO4 2+ – copper (II) or cupric ion Cu ion ClO3 2+ – mercury (I) or mercurous ion Hg2 chlorite ion ClO2 mercury (II) or mercuric ion Hg2+ hypochlorite ion ClO– 2+ – lead (II) or plumbous ion Pb nitrate ion NO3 4+ – lead (IV) or plumbic ion Pb nitrite ion NO2 iron (II) or ferrous ion Fe2+ permanganate ion MnO– iron (III) or ferric ion Fe3+ carbonate ion 2– CO3 4 2+ – manganese (II) ion Mn hydrogen carbonate or bicarbnate ion HCO3 nickel (II) ion Ni2+ chromate ion CrO2– tin (II) or stannous ion 2+ dichromate ion Cr O2– Sn 2 4 4+ 2– tin (IV) or stannic ion Sn peroxide ion O2 2+ 2–7 chromium (II) ion Cr sulfate ion SO4 3+ – chromium (III) ion Cr hydrogen sulfate or bisulfate ion HSO4 cobalt (II) ion Co2+ sulfite ion SO2– 3+ – cobalt (III) ion Co hydrogen sulfite or bisulfite ion HSO3 3+ ퟑ3─ bismuth (III) ion Bi phosphate ion PO4 2– hydrogen phosphate ion HPO4 – dihydrogen phosphate ion H2PO4 3– borate ion BO3 2– oxalate ion C2O4 Note: Ions in bold type are very common and must be memorized first!!!

MONATOMIC IONS I A VII A VIII A

− H+ H II A III A IV A V A VI A

Li+ Be2+ C4− N3− O2− F−

+ 2+ 3+ 4− 3− 2− − Na Mg Al Si4 P S Cl III B IV B V B VI B VII B VIII B VIII B VIII B I B II B 2+ 2+ 2+ + + 2+ Cr 2+ Fe Co 2+ Cu 2+ 3− 2− − K Ca 3+ Mn 3+ 3+ Ni 2+ Zn As Se Br Cr Fe Co Cu Sn2+ Rb+ Sr2+ Ag+ Cd2+ Te2− I− Sn4+

2+ + 2+ Pb 3+ + 2+ Au Hg 2 Bi Cs Ba 3+ 2+ 4+ Au Hg Pb

n+ E metallic elements that form a single stable monatomic cation: Ba2+ is barium ion, Al3+ is aluminum ion, etc.

En+ metallic elements that form several stable monatomic cations: 3+ 2+ 2+ Cr is chromium (III) ion, Hg is mercury (II) ion, etc.; Hg 2 is a polyatomic ion called mercury (I) ion

En− nonmetallic elements; each forms a single stable monatomic anion: F− is fluoride ion, Si4− is silicide ion, etc.

ions that do not exist in aqueous solutions; they react with water by accepting either H+ − + − + − or OH ions (small amounts of H and OH ions are always present in water: H2O ⇆ H + OH )

OXYACIDS AND OXYANIONS 2─ SO3 sulfite ion

minus H+

─ HSO ─ NO2 3 nitrite ion hydrogen sulfite ion minus H+ minus H+

HNO2 H2SO3 nitrous acid sulfurous acid

minus O minus O

HNO3 H2CO3 H2SO4 H3PO4 nitric acid carbonic acid sulfuric acid phosphoric acid

minus H+ minus H+ minus H+ minus H+

─ ─ HCO3 HSO ─ H2PO4 NO ─ 4 3 hydrogen hydrogen dihydrogen nitrate ion carbonate ion sulfate ion phosphate ion

minus H+ minus H+ minus H+

HPO 2─ 2─ 2─ 4 CO3 SO4 hydrogen carbonate ion sulfate ion phosphate ion

minus H+

3─ PO4 phosphate ion OXYACIDS* OXYANIONS

− H2O (HOH) water OH hydroxide ion

− HC2H3O2 (aq) acetic acid C2H3O 2 acetate ion

− HClO4 (aq) perchloric acid ClO 4 perchlorate ion

− HClO3 (aq) chloric acid ClO 3 chlorate ion − HClO2 (aq) chlorous acid ClO 2 chlorite ion HClO (aq) hypochlorous acid ClO − hypochlorite ion

− HNO3 (aq) nitric acid NO 3 nitrate ion − HNO2 (aq) nitrous acid NO 2 nitrite ion

2− H2CO3 (aq) carbonic acid CO 3 carbonate ion

− HCO 3 hydrogen carbonate ion ( ion)

2− H2SO4 (aq) sulfuric acid SO 4 sulfate ion

− HSO 4 hydrogen sulfate (bisulfate ion)

2− H2SO3 (aq) sulfurous acid SO 3 sulfite ion

− HSO 3 hydrogen sulfite ion (bisulfite ion)

3− H3PO4 (aq) phosphoric acid PO 4 phosphate ion

2− HPO 4 hydrogen phosphate ion

− H2PO 4 dihydrogen phosphate ion

* Pure covalent molecular compounds or their aqueous solutions. Usually, only acids

with the highest number of oxygen atoms (HClO4, HNO3, H3PO4, H2SO4) can be obtained in pure form. Those are also stable in aqueous solutions. All other acids exist only as aqueous solutions. Organic acids, such as acetic acid, are stable in pure form and in aqueous solutions.

NONOXYACIDS AND NONOXYANIONS

COMPOUNDS ACIDS ANIONS

pure substances: aqueous solutions: exist in ionic − only HX molecules HX dissolved in H2O or as X (aq) in aqueous solutions

HF(g) HF(aq) hydrofluoric acid F− fluoride ion

HCl(g) hydrogen chloride HCl(aq) hydrochloric acid Cl− chloride ion

HBr(g) hydrogen bromide HBr(aq) hydrobromic acid Br− bromide ion

HI(g) hydrogen iodide HI(aq) hydroiodic acid I− iodide ion

2− H2S(g) hydrogen sulfide H2S(aq) hydrosulfuric acid S sulfide ion HS− hydrogen sulfide ion

HCN(g) HCN(aq) hydrocyanic acid CN− cyanide ion

PREFIXES AND SUFFIXES IN THE NAMES OF ACIDS

AND THE CORRESPONDING ANIONS

Number of Acid Anion Oxygen Atoms Greatest per– ...... –ic acid per– ...... –ate ion

Greater ...... –ic acid ...... –ate ion

Smaller ...... –ous acid ...... –ite ion

Smallest hypo– ..... –ous acid hypo– ..... –ite ion

None hydro– ...... –ic acid ...... –ide ion

EXAMPLE:

HClO4(aq) perchloric acid ClO4 perchlorate ion −

HClO3(aq) chloric acid ClO chlorate ion − 3 HClO2(aq) chlorous acid ClO chlorite ion − 2 HClO(aq) hypochlorous acid ClO hypochlorite ion − HCl(aq) hydrochloric acid Cl chloride ion −