Chapter 3 -Chemistry
Things to know about Octet rule:
1. an atom that looses 1 or more electron becomes a positively charged ion called a cation. 2. an atom that gains on or more electron becomes a negatively charged ion called anion. 3. the rule does not apply to transition elements (forms 2 or more different positive charges)
Rules or Ionic compounds
1. the more electronegative atom gains 1 or more valence electrons and become an anion 2. the less electronegative atom loses 1 or more valance electrons and becomes a cation 3. the compound formed by the combination of an anion and a cation is called an ionic compound
Rules for naming cations
1. use roman numeral enclosed in () following the name of the element to show the charge 2. Use the suffix -ous to show the lower + charge and -ic to show higher + charge.
Non-metals
2 non-metals will always be polar
Aluminum ion
Al3+
Barium ion
Ba2+
Calcium ion
Ca2+
non-polar
Carbon + hydrogen will always be non polar
Cu+
Copper(I) ion *cuprous ion
Cu2+
Copper(II) ion *cupric ion
Hydrogen ion
H+
Fe2+
Iron (II) ion *Ferrous ion
Fe3+
Iron(III) ion *Ferric Ion
Potassium ion
K+
Lithium ion
Li+
Magnesium ion
Mg2+
example of ionic compound
Na* + Cl 7*= Na+ Cl 8*
Sodium ion
Na+
KCl
Potassium chloride
Strontium ion
Sr2+
Sn4+
Tin (IV) ion * stannic ion
Sn2+
Tin(II) ion *Stannous ion
covalent bonds
a covalent bond is formed by sharing one or more pairs of electrons. Ex: H*+H*= H--- H
Electronegativity
a measure on atom's attraction for the electron it shares in a chemical bond with another atom. Fluorine is the most electronegativity element
Ionic compounds
according to the lewis model an ionic bond is formed by the transfer of one or more valance electrons from an atom of lower electronegativity to an atom of higher electronegativity.
Forming chemical bonds
according to the lewis model- an atom may lose or gain enough electrons to acquire a filled valence shell and become an anion.
Resonance
all structures must: 1. have the same number of valance electrons 2. obey the rules of covalent bonding *no more than 2 electrons in the valance shell of H *no more than 8 electrons in the valance shell of a 2nd period element *3rd period elements such as P and S, may have up to 12 electrons in their valance shell
AlCl3(bottom)
aluminum chloride
NH4OH
ammonium hydroxide
F-
anion name: Fluoride
H-
anion name: Hydride
I-
anion name: Iodide
O2-
anion name: Oxide
S2-
anion name: Sulfide
Br-
anion name: bromide
Cl-
anion name: chloride
BaH2
barium hydride
CaCO3
calcium carbonate
CuSO4
copper(II) sulfate, cupric sulfate
Polar covalent bond
electron sharing is not equal. 0.5 to 1.9. 2 nonmetals or a nonmetal and a metalloid
Nonpolar covalent bond
electrons are shared equally. less than 0.5. 2 nonmetals or a non-metal and a metalloid
Cations
elements of groups 1A, 2A, 3A form only one type of cation.
Ions of period 1 and 2
elements with charges greater than 2+ are unstable. example: boron does NOT lose its three valence electrons to become B3+, or does carbon lose its 4 electrons to become C4+
Monatomic Anions
for monatomic (containing only 1 atom) anions, add ide to the stem name
Naming Cations
for naming cations derived from transition and inner transition elements, most of which form more than one type of cation, there are 2 options.
Aluminum ion, Al3+, and sulfide ion S2-
form Al2(bottom)S3-(bottom)
Barium ion, Ba 2+, and iodide ion,
form BaI2-(bottom)
Lithium ion, Li+, and Bromide ion, Br-,
form LiBr
sodium ion, Na+, and bicarbonate ion, HCO-3(bottom)
form NaHCO3-(bottom)
type of bond: ionic
greater than 1.9. a metal and a nonmetal
molecular compounds
in which all bonds are covalent
FeCO3
iron(II) carbonate, ferrous carbonate
Fe2(CO3)3
iron(III) carbonate, ferric carbonate
Ionic bond
is the result of force of attraction between a cation and anion
LiBr
lithium Bromide
LiH
lithium hydride
MgO
magnesium Oxide
Hg+
mercury(I) ion *mercurous ion
ionic compounds that contain polyatomic ions
name the positive ion first and followed by the name of the negative ion
Ionic
rows 1 and 7, row 2 and 7 (most of them are ionic) it must be greater than 1.9
Ag2S
silver sulfide
NaH2PO4
sodium dihydrogen phosphate
NaNO3
sodium nitrate
Vesper model
the four regions radiate from carbon at angles of 109.5. the electron pair geometry is tetrahedral
Octet rule
the tendency of group 1A-7A elements to react in ways that achieve an electron configuration of 8 valance electrons.