1 / 15

Compound Names and Formulas

Compound Names and Formulas. Ch 5.2 and 5.3. Polyatomic Ions. “Poly” means many, and “Atomic” means atom, so… Polyatomic ions are ions made of two or more atoms Examples: Hydrogen Carbonate, HCO 3 - Hydroxide Ion, OH - Ammonium Ion, HN 4 +. Polyatomic Ions.

asis
Download Presentation

Compound Names and Formulas

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. Compound Names and Formulas Ch 5.2 and 5.3

  2. Polyatomic Ions • “Poly” means many, and “Atomic” means atom, so… • Polyatomic ions are ions made of two or more atoms • Examples: • Hydrogen Carbonate, HCO3- • Hydroxide Ion, OH- • Ammonium Ion, HN4+

  3. Polyatomic Ions • The charge applies to the whole polyatomic ion • Example: Nitrite Ion, NO2- • The negative charge applies to the oxygen and to the nitrogen

  4. Naming Ionic Compounds • Ionic compounds formed between positive ions (cations) and negative ions (anions) • Naming anions (negative ions): • Keep the same beginning, and change the ending • Examples: • Fluorine, F  Fluoride Ion, F- • Chlorine, Cl  Chloride Ion, Cl- • Oxygen, O  Oxide Ion, O-2 • Nitrogen, N  Nitride Ion, N-3

  5. Naming Ionic Compounds • Keep the cation (positive ion) the same, and change the anion (negative ion) to its altered state (seen on previous slide) • Examples: • NaF • Made from Na+ and F- • Cation, Sodium Na+ Keep the same • Anion, Fluorine F- Change to Fluoride • Write the cation first, always • Therefore, the name is sodium fluoride

  6. So how do you name this? • FeO vs. Fe2O3 • Cannot just say iron oxide—have to be more specific • To specify, we look at the charge of the cation (positive ion/the metal/the first atom) • Transition metals can have different charges depending on what they are bonded to

  7. Naming Ionic Compounds • FeO • Fe is a transition metal and the charge can vary • Therefore start with O and figure out its charge • Oxygen is group 16, therefore forms -2 charges • Therefore Fe must have +2 charges to balance out the oxygen • Write the charge of the cation (Iron, +2) in parentheses after the metal, Iron (II) • Name of FeO: Iron (II) Oxide

  8. How do you name… • Fe2O3 • What is the charge of one oxygen ion? • -2 • There are three oxygen atoms, therefore oxygen has an overall charge of (-2)(3) = -6 • Therefore iron must contribute a +6 charge to balance out the oxygen • There are two iron atoms, so each atom must have a +3 charge because (2)(+3) = +6 • Since iron has a charge of +3, the name of Fe2O3 is iron (III) oxide

  9. Writing formulas… • What is the chemical formula for aluminum fluoride? • Use Table 4 (Page 159)Charge of an aluminum ion is +3 • Use Table 5 (Page 160)Charge of a fluoride ion is -1 • Step 1: Write down ions beside each other, with the cation first • Al+3F-

  10. Writing ionic formulas… • What is the chemical formula for aluminum fluoride? • Al+3F- • Trick! Cross the charges to get the amount of ions in each. • Becomes AlF3

  11. Let’s see it another way…

  12. Practice… • Write lithium oxide • Li+1 • O-2 • Write the cation first: Li+1 O-2 • Cross the charges • Therefore lithium oxide is Li2O

  13. Practice • Write beryllium chloride • Be+2 • Cl-1 • Write cation first. • Cross the charges. • So beryllium chloride is BeCl2

  14. Practice • Write titanium (III) nitride • Remember: (III) corresponds to charge • So Ti+3 • Nitride-3 • Write the cation first. • If you cross the charges, you get Ti3N3 which can be reduced to a ratio of 1:1 • So titanium (III) nitride is TiN

  15. Challenge Practice • Write cobalt (III) hydroxide • Co+3 • Hydroxide ion, OH- • Write the anion first, then cross the charges! • Co(OH)3 • Remember to keep OH is parentheses since it is one polyatomic ion!

More Related