1 / 23

TYPES OF COMPOUNDS

TYPES OF COMPOUNDS. Chemical Family Resemblances. Binary salts. Binary salts are made of a metal and a nonmetal – only two different elements. Examples: NaCl, MnO 2 Binary salts are named with the name of the metal first, then the name of the nonmetal with the “-ide” ending. Example: K 2 O

hong
Download Presentation

TYPES OF COMPOUNDS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. TYPES OF COMPOUNDS Chemical Family Resemblances

  2. Binary salts • Binary salts are made of a metal and a nonmetal – only two different elements. Examples: NaCl, MnO2 • Binary salts are named with the name of the metal first, then the name of the nonmetal with the “-ide” ending. Example: K2O potassium oxide

  3. FORMULAS • The formula unit is the simplest ratio of ions in the salt. Ga2O3 2:3 ratio of gallium atoms to oxygen atoms 2 gallium atoms and 3 oxygen atoms make one formula unit

  4. formulas • Electrons and charge are conserved in a formula unit. • 2 gallium atoms have a total of 6 valence electrons and no charge • 3 oxygen atoms have a total of 18 valence electrons and no charge • so gallium oxide (Ga2O3) has 18+6=24 valence electrons and no charge

  5. conservation • Conservation of electrons and charge in gallium sulfide (Ga2S3)

  6. conservation

  7. oxidation numbers • Oxidation number of an ion is equal to the charge on an ion after it gains or loses electrons. • All atoms gain or lose electrons to try to attain a noble gas configuration (8 valence electrons) • Noble gases have no oxidation numbers

  8. oxidation numbers • Metals – lose all valence electrons, positive (+) oxidation numbers • Metals lose electrons so as to expose full valence shell in next lower level • Alkali metals and hydrogen are +1 • Alkaline earths are +2 • Aluminum and friends are +3

  9. oxidation states • Tin and lead are +2 or +4 • Transition metals vary • Nonmetals – gain electrons, negative (-) oxidation numbers • Enough electrons are gained to complete the valence shell • Oxygen is always –2, and sulfur is –2 unless with oxygen

  10. ternary salts • Halogens are –1 unless with oxygen • Nitrogen and phosphorus are –3 unless with oxygen or halogens • Ternary salts are composed of more than two elements • Ternary salts contain polyatomic ions • Polyatomic ions contain more than one atom example: CO3-2 carbonate

  11. polyatomic ions • Polyatomic anions have a (-) charge, and polyatomic cations a (+) charge • Polyatomic ions act as a unit – the subscripts of the formula may not be changed • Names and formulas • Most names end in “-ate” or “-ite”, which means the ion contains oxygen

  12. naming polyatomic ions • Examples: sulfate (SO4-2), sulfite (SO3-2) • The ending and prefix (if present) indicate the relative number of oxygen atoms in the formula. perchlorate ClO4– chlorate ClO3– chlorite ClO2– hypochlorite ClO–

  13. polyatomic cations • The “-ium” ending means a positive ion (hydronium, H3O+, and ammonium, NH4+) • Multiple ions are indicated by parentheses and a subscript • Example: magnesium hydroxide is Mg(OH)2 • Ammonium sulfide: (NH4)2S

  14. formulas with polyatomic ions • Formulas are made the same way as the binary salts, with the criss-cross method + -2 Na CO3 2 ( ) Ca+2 Ca OH- 2

  15. Naming ternary salts • Ternary salts are named with the metal name first, then the name of the polyatomic ion K3PO4 potassium phosphate

  16. Transition metal salts • Many transition and “other” metals have more than one oxidation number • These numbers are found on some periodic tables • Metals to know: Fe (+2, +3), Cu (+1, +2), Ag (+1), Zn (+2), Sn (+2, +4), Pb (+2, +4), Bi (+3, +5)

  17. transition metal salts • Oxidation number of transition metal is indicated by a Roman numeral in parentheses • FeCl3 is iron (III) chloride • Name these: CrO chromium (II) oxide Cr2O3 chromium (III) oxide CrO3 chromium (IV) oxide

  18. transition metal salts • The Roman numeral is not needed if there is only one oxidation state for the metal (i.e. Zn, Ag, Sc) • The Roman numeral is also used for “other” metal salts like tin (II) fluoride (SnF2, formerly used in toothpaste) • Transition metal salts are often brightly colored

  19. hydrates • Hydrates are salts that have water incorporated into the crystal structure • The water is usually associated with the cation • The number of water molecules in the crystal are specified in the formula MgCl2. 6H2O

  20. hydrates • The dot means they are not chemically bonded • Names of hydrates – “hydrate” plus a prefix is added to the salt name MgCl2. 6H2O is magnesium chloride hexahydrate • Prefix indicates the number of water molecules

  21. hydrate prefixes mono = 1 di = 2 tri = 3 tetra = 4 penta = 5 hexa = 6 hepta = 7 octa = 8 nona = 9 deca = 10

  22. Formation of hydrates • Hydrates can be formed when certain salts are crystallized from water. • Example – CuSO4. 5H2O {copper (II) sulfate pentahydrate} • Hygroscopic compounds become hydrates by taking water from the air.

  23. Formation of Hydrates • Example – sodium carbonate becomes sodium carbonate decahydrate (Na2CO3. 10H2O) • Deliquescent compounds take enough water from the air to form concentrated solutions – examples: calcium chloride (CaCl2), sodium hydroxide (NaOH)

More Related