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.