a statement in chemical symbols that represents the composition of a substance
symbol in chemical formula
subscripts in chemical formula
how many of each
composition= H, O amount= 2,1
2 Types of Chemical Formulas
Empirical and Molecular Formulas
-simplest whole number ratio that elements can combine to form a compound
- the exact number of atoms that are present in each elements for one molecule of a substasnce
- the smallest particle of a substance that can exist and still have the composition and properties of a substance
2 Types of Molecules
Single Atom Molecules & Double Atom Molecules
Single Atom Molecules
- Noble Gases (elements and molecules ex) Xenon
Double Atom Molecules
- two or more atoms of the same element from a molecule - 7 Diatomic Elements ex) Ozone (3 oxygen atoms)
- 2 or more diff. elements chemically combined like H20
Benzene (emp and molecular formula)
C6H6- molecular CH- empirical
C2H2- molecular CH- empirical
H20- molecular H20- empirical
NH3- molecular NH3- empirical
2 Types of Compounds
Ionic Compound and Molecular Compound
when metallic elements combine chemically with non-metallic elements...
one or more elemets is transferred to the non-metal
- 1, 2, 3 valence electrons
metals have a low...
-ionization energy (energy requiered to remove the most loosely held electrons) - electronegativity (1, 1/2)
1, 5, 6, 7 valence electrons
tend to have high...
ionization energies and electronegativety
rating scate for electronegativety
- ranks atoms ability to attract electrons in this bond - 0-4 (best electronegatively-- Fluroine)
- transfer electron for a stable octet - crystal lattice (repeatin pattern in a solid phase)
- force of attraction
sodium transfers electron to cholorine (metal to non-metal)
1:1 ratio keeps building
What kind of formuals do ionic coumpounds have?
More ions can join...
as long as the ratio is kept and continued
Rules for writing Binary Ionic Compounds
1) the least electromagnetic element goes first (the metal goes first- cation ion goes first) 2) Assign ionic charges (look at valence structure) 3) Assign enough of each atom so the compound is electrically neutral # of (+)= # of (-)
what rule should you use?
metal, non-metal ends in
Ternary Ionic Compounds have...
PAI (poly atomic ions)
possibility types of Ternary Ionic Compounds
a) metal+ and PAI- b) PAI+ and non-metal (ide) c) PAI+ and PAI-
when can you drop parenthesis of PAI number?
when the number outside of the parenthesis is 1
never cahnge------ of PAI
state or charge
2 naming systems of ionic compounds of more that one oxidation numner (state)
1) Stock System 2) Latin Root- suffix
- oxidation # - IUPAC - metal ( ) ending
ex) CU+1 chromate
copper (1) chromate copper(11) chhromate
Latin root- ous (lowest possible charge) - ic (next lowest)
ex) latin root
cuprous chromate cuproc chromate
can you reduce within PAI
To find charge originally
After usign latin root for first too, then you go to the...
Instead of Hg+1
Cr +2, +3
Cu +1, +2
Fe +2, +3
Sn +2, +4
Pb +2, +4
Sb +3, +5
Hg +1, +2
Mercurous Mercuric exists only as 2 (Hg+2)+2
O-1 can not be written cause you need 2 of them peroxide (PAI)