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22.3 Notes Continued. Part C. Objectives. Write formulas and names for covalent compounds. Covalent compounds. Made of just nonmetals Share electrons Smallest piece is a molecule Can’t be held together because of opposite charges Can’t use charges to figure out how many of each atom. - PowerPoint PPT Presentation
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22.3 Notes Continued
Part C
Objectives
Write formulas and names for covalent compounds
Covalent compounds
Made of just nonmetals Share electrons Smallest piece is a molecule Can’t be held together because of
opposite charges Can’t use charges to figure out how
many of each atom
Covalent/Molecular compounds
Ionic compounds use charges to determine how many of each element.
Molecular compounds name tells you the number of atoms.
Uses prefixes to tell you the number
Naming Covalent Compounds
Prefix element name Prefix element name-ide The last vowel of the prefix is dropped when the
second element begins with a vowel as in pentoxide• No double vowels when writing names (oa oo)• Often the prefix mono- is omitted from the first element
when naming• Many times it is also omitted from 2nd element, though
it is used for emphasis in some cases
Examples
Carbon dioxide – CO2
Dihydrogen monoxide – H2O Dinitrogren pentasulfide – N2S5
Tricarbon tetrafluoride – C3F4
Name These
N2O NO2 Cl4O7 NBr3 BaCl5
Writing formulas for Covalent Compounds
Simply write the chemical symbol Subscript is derived from the
prefix Mono = 1, di = 2, tri = 3, ect
Write formulas for these
diphosphorus pentoxide tetraiodide nonoxide sulfur hexaflouride Carbon tetrahydride phosphorus trifluoride
Hydrates
• An ionic compound that has water chemically attached to its ions and written into its chemical formula
Hydrates pg. 708
• These same prefixes are used when naming the hydrates previously discussed.
• The main ionic compound is named the regular way, but the number of water molecules in the hydrate is indicated by the Greek prefix.
Chemical formula • # H2O
Hydrates
BeBr * 3 H2O
Calcium nitride hexahydrate
In-Class Assignment/Homework
Finish naming Molecular Compounds WKT
Naming practice on the board