1 / 26

Chemical Names and Formulas

Chemical Names and Formulas. The naming of the compounds depends on the type compound: Molecular compounds Ionic compounds Binary ionic compound Containing a transition metal Containing a polyatomic ion Acids Binary acids Oxy Acids. Chemical Names and Formulas.

vikkil
Télécharger la présentation

Chemical 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. Chemical Names and Formulas • The naming of the compounds depends on the type compound: • Molecular compounds • Ionic compounds • Binary ionic compound • Containing a transition metal • Containing a polyatomic ion • Acids • Binary acids • Oxy Acids

  2. Chemical Names and Formulas • In naming molecular compounds • Prefixes are used to indicate the number of atoms in each molecule • It would be impossible to determine the formula without the prefixes

  3. Chemical Names and Formulas • The naming system is straightforward except… • We never begin a formula name with mono • CS2 – Carbon disulfide • We eliminate the –a or –o in the prefix if the element begins with a or o • N2O5 – dinitrogen pentoxide • We change the second element’s ending to -ide

  4. Chemical Names and Formulas • Ionic compounds are compounds made up of ions of opposite charges • A chemical formula is the lowest whole number ratio of the ions present in the compound Na2Cl2 can be reduced to NaCl • The ratio of the ions will depend on the charge of those ions

  5. Chemical Names and Formulas • The charge is sometimes referred to as the oxidation number or oxidation state • Ions formed from one atom are called monoatomic ions

  6. Chemical Names and Formulas • Binary ionic compounds are made up of only 2 different elements • There can be more than 2 or more atoms though • NaCl • K2O • Al2S3

  7. Chemical Names and Formulas • To name a binary ionic compound • Write the name of the cation first (always a metal) • Write the name of the anion, but change the ending to –ide • Note that any subscripts do not change the name NaCl sodium chlorine → chloride sodium chloride

  8. Chemical Names and Formulas K2O Al2S3

  9. Chemical Names and Formulas • Name the following compounds • KI • MgO • SrS • BeF2 • Li2O • Al2O3 • Cs3N • Ba3P2

  10. Chemical Names and Formulas • To write formulas it is important to remember that the charges on the compound must be balanced • Same total number of positive and negative charges • Determine if the charges are balanced • Sodium chloride • Lithium oxide • Potassium iodide • Beryllium bromide • Sodium nitride

  11. Chemical Names and Formulas • When charges are not balanced, it is necessary to add subscripts • They represent the quantity of each element • No subscript equals 1 atom • Li+ O2- the charges are not equal • There is only one positive and two negatives • We need another positive charge to make them equal • Li2O

  12. Chemical Names and Formulas • Write formulas for the following compounds • Sodium sulfide • Potassium iodide • Calcium bromide • Aluminum oxide • Boron bromide • Rubidium selenide

  13. Chemical Names and Formulas • Sometimes the metal in a compound is a transition metal • Groups 3-12 contain the transition metals • Transition metals can move their electrons from the s to the d orbitals • This gives them various oxidation numbers or charges • For example iron can be either Fe2+ or Fe3+

  14. Chemical Names and Formulas • Since these metals do not have a set charge, we must indicate their charge in the name, using Roman numerals • For example look at the three possible compounds that chromium can form with oxygen • Cr2+ and O2- yields CrO called chromium (II) oxide • Cr3+ and O2- yields Cr2O3 called chromium (III) oxide • Cr6+ and O2- yields CrO3 called chromium (VI) oxide

  15. Chemical Names and Formulas • When writing a formula for a transition metal compound remember that the charge of the metal is in the parentheses • Write formulas for the following: • Lead (IV) chloride • Iron (III) oxide • Titanium (II) nitride • Niobium (V) bromide • Tin (II) oxide

  16. Chemical Names and Formulas • Almost all metals get a roman numeral to show the charge • The following do NOT use a roman numeral • Group 1 metals • Group 2 metals • Al3+ • Zn2+ • Ag1+

  17. Chemical Names and Formulas • To write formulas for compounds containing transition metals, we must work backwards: • You will always start with a balanced formula: FeO CoCl2 Au3N

  18. Chemical Names and Formulas • Polyatomic ions are ions that contain more than one atom • SO42- • OH- • PO43- • NH4+ • It is important to note that the charge is distributed throughout all the atoms in the ion • Not only on the last atom!

  19. Chemical Names and Formulas • To name a formula containing a polyatomic ion we must first identify it • If the ionic compound formula contains more than two elements, you have a polyatomic ion present • We do not change the endings of any polyatomic ion

  20. Chemical Names and Formulas • For example, NaOH is • Na2SO4 is • Ca(OH)2is We do not include the subscript outside of the parentheses when naming the compound

  21. Chemical Names and Formulas • To write formulas of ionic compounds containing polyatomic ions: • Calcium carbonate - • Charges are balanced so • Calcium hydroxide - • Charges are not balanced - we need an additional OH-,but we must use parentheses – • Sodium carbonate – • Charges are not balanced – we need an additional Na+, but we do not need parentheses – • Parentheses are only needed when you add a subscript to a polyatomic ion

  22. Chemical Names and Formulas • Bases (ending in OH-) are named as taught before • A common base with a different name is NH3 –ammonia • Acids have a completely different naming system • There are two types of acids • Binary acid – contains H+ and anion(-) • Oxy (Ternary) acid - contains H+ and polyatomic ion(-)

  23. Chemical Names and Formulas • To name a binary acid • Use a prefix hydro • Add the anion name with an –ic ending • Finish with acid • HCl becomes hydrochloric acid • HBr becomes hydrobromic acid • H2S becomes hydrosulfuric acid

  24. Chemical Names and Formulas • To write a formula for a binary acid • Identify that it’s a binary acid – must start with hydro • Write the H+ and the other element with the charge • Balance the charges • Hydronitric acid becomes • H+ N3- • H3N

  25. Chemical Names and Formulas • To name an oxy (ternary) acid • Start with the polyatomic name • If the polyatomic ends in -ate, change the ending to –ic • If the polyatomic ends in –ite, change the ending to –ous • Finish with acid • H2SO4 becomes sulfuric acid • H2SO3 becomes sulfurous acid

  26. Chemical Names and Formulas • To write a formula for an oxy (ternary) acid • Identify that it’s an oxy acid (no hydro in name) • Start with H+ • Add name of polyatomic • Remember that -ic means it ends in -ate and -ous means it ends in -ite • Balance the charges • Nitric acid becomes • H+ NO3- • HNO3

More Related