ATOMS, MOLECULES,& IONS

Dalton: atomic theory

Atomic Structure & WeightsP. Table

Molecules & Compounds

CMPDS: formula, name

Molecule/Cmpd

Cmpd: metal + nonmetal transfer of e- metal lose & nonmetal gains

Law Mass Conservation

Total mass not D in chem rxn. - total mass reactants = total mass pdts

Molecule: nonmetal + nonmetal share e- = or un= sharing

H2 + O2 -------> H2O 1.0 16.0 2.0 + 16.0 2.0 + 32.0 34.0 = 18.0

2 H2 + O2 ------> 2 H2O 2*2.0 + 32.0 2*18.0 36.0 = 36.0

Mass is neither created nordestroyed, but changes form

Definite CompositionLaw: cmpd composed of elements in a fixed ratio by weight

Fraction Mass: fraction each element contributes to total mass of cmpd

% Mass: % mass each element contributes to total mass of cmpd

Multiply Proportions

cmpd. mass totalelementeach of mass Fract.Mass

% mass = fraction mass * 100

When 2 elements combine to give to diff. substances, the masses of elements that form molecule can be expressed as a simple whole #

CO CO2

43% C 57% O 27% C 73% O

Elements: simplist form of matter; only 1 kind of atom; p.table; not broken down any further

Compound: 2+ diff atoms bonded; fixed ratio by mass; properties diff than individual atoms; decomposed into simplier subst (chem)

Mixture: 2+ diff subst; not chem react; mix in any diff amts; sep physical means

TERMS

Atomic Number: identifies which element # of protons

Mass Number: atomic mass rounded to nearest whole number # protons + # neutrons

Atomic Mass: relative ave mass of element including % of all isotopes

Isotope: diff form of same elementdiff # of neutrons

Democritus - particles atomosNewtonDalton - atomic theory, 4 postulatespg 42

Greeks: 4 elements earth - air - water - fire

1. All matter composed of identical atoms

2. Atoms that make up elements are diff diff. elements ---- atom make-up diff

3. Atoms neither created nor destroyed in chem rxns. Chemical rxns only involve change in atom ratios to produce new subst., not change in atoms themselves

4. Cmpds. are composed of diff atoms in fixed ratio

Dalton’s theory explained laws of

“……. definite composition” “……. conservation of mass (mattter)”

ATOMIC STRUCTURE pg 48

particles charge mass location determine p+, protonsn0, neutronse-, electrons

“1+”“0”“1-”

110

nucleusnucleusoutside

elementisotopechemistry

RutherfordAu foil

e-: -1.602*10-19 Cp+: + 1.602*10-19 C

p+ 1.0073 amun0 1.0087 amu

e- 5.486*10-4 amu

1836 e- =1 p+ mass

ISOTOPE NOTATION

mass #p+ + n0

p.table

Xatomic # # p+

+/- charge

# n0

mass# - atomic#p.table

p.table

31

59

28Ni

50

88

38Sr

What infocan you

get

Element: Symbol: Atomic #:

Mass #: # n0

Notation with 2 less e-’s

Element: Phosphorus Symbol:

This is element # , therefore, it is Atomic #

Mass #: # n0

Write notation with 3 more e-’s

Now, try notationfor O-15

RELATIVE ATOMIC WEIGHT

• NEON 20.1797

3 Isotopes

20Ne

21Ne

22Ne

Isotope Mass % Abundance

19.9924356

20.9938428

21.9913831

90.48 %

0.27 %

9.25 %

20Ne

21Ne

22Ne

19.9924356

20.9938428

21.9913831

0.9048

0.0027

0.0925

*

*

*

=

=

=

18.08915573

0.056683376

2.034202937+

20.18004204

ATOMIC MASS SCALE

1 amu = 1.66054*10-24 g 1 g = 6.02214*1023 amu

particles charge mass p+, protonsn0, neutronse-, electrons

“+”“0”“-”

110mole

Atomic Weight

H = 1.00794 = 1

He = 4.0026 = 4

Co = 58.9332 = 59

1 p+

0 n0

2 p+

2 n0 27 p+

32 n0

PERIODIC TABLE

incr atomic #

rows: periods/series

columns: families/groups

families, series,metal/nonmetal/metaloid last element not reactive;

complete filled e- shell

similar properties;same # valence e-

ELEMENT CHARACTERISTICS

metalnonmetal

metalloid

Usually solids @ room tempShine w/ luster, metallic lusterDuctile: form into a wire, stretch when pulledMalleable: able to hammer (pound) into shape, deform w/o breakingConducts heat & electricityAlways “+” charge70% of elementsForm alloys w/ other metals Brass, Bronze Cu + Zn Cu + Sn

No luster or shineNot malleableNot ductileForms molecules w/ each other or other elementsNot conduct20 elementsCan form “+” & “-” charges

Properties similar to metals & nonmetalsConduct electricity, semiconductor properties B, Si, As, Te, Ge, Sb

MOLECULES/CMPDS

molecules: 2+ diff atoms bonded together in any ration C2H6 C2H4 C2H2

diatomics: 2 of same atom combined 7: H, N, O, F, Cl, Br, I H2, N2, O2, F2, Cl2, Br2, I2

cmpds: combine +/- charged ion

metal + nonmetalcation(+) anion(-)

Na+1Cl-1 Mg+2O-2

NaCl MgOSodium Chloride Magnesium Oxide

Na+1O-2 Mg+2Cl-1

Na2O MgCl2

Sodium Oxide Magnesium Chloride

NOTICE:= opp charges, &

diff chargesBinary - 2 element cmpd; + metal & - non

REVIEW: Structure of an Atom

3 subatomic particles: p+; no; e-

Z: atomic number; # p+; i.d. element

A: mass number; p+ + no

Atomic SymbolIsotope Notation

N: # no; A - Z

echN

AZ X arg

FORMS: K3919

120

3919

K20

3919

K

Potassium - 39 K - 39

p+ --> elementno --> isotope

e- --> chemistry (E)

ISOTOPE same element, same # p+, only change # no

Diff. make-up of same element

1) Not change element itself, same # p+

2) Diff. # of n0

3) Change atomic weight/mass

result is change in Density

ATOM ---charged

Termed: ION Cation: + charged Anion: - charged

# p+ > # e- “+” charge# p+ < # e- “-” charge

same element, same # p+, only change # e-

# p+ = # e- no charge to atommagnitude p+ charge = that of e- but “+” in sign

PERIODIC TABLE- arranged atomic #- 7 rows; periods/series- 18 columns; groups/families

elements in each group – similar chemical properties

Groups numbered in 2 ways Group A/B Group 1 - 18

Group A/B Main Group “A” : first 2 col. left, last 6 col. rgt. Transistion Metals “B”: 10 col. in middlde

Group 1 – 18 Each col. numbered 1 thru 18, left to right

Inner Transition Metals (Rare Earth) Lanthanide Series; elements 58 - 71 Actinide Series; elements 90 – 103 14 col., not numbered

1A : ALKALI METALS

elements 1st col.: Li, Na, K, Rb, Cs, Fr

Shiny, soft, low melting pt.

React violently w/ H2O produce alkaline (or basic)

Not found in pure state, combined w/ other elements in cmpd.

2A: ALKALINE METALS

elements 2nd col.: Be, Mg, Ca, Sr, Ba, Ra

shiny, silvery

less reactive than 1A

Not found in pure state

7A: HALOGENS (HALIDES)

elements next to last col.: F, Cl, Br, I, At

colored, corrosive nonmentals

found combined w/ elements

Halogen (HALS) - salt

8A: NOBLE GASES (INERT)

elements last col.: He, Ne, Ar, Kr, Xe, Rn

colorless gases, nonmetals

low reactivity w/ other subst.

INERT - nonreactive

DiatomicsH2 -- N2 -- O2 -- F2 -- Cl2 -- Br2 -- I2

Tetratomic: P4

Octatomic: S8 -- Se8

Polyatomic Ions: group of 2+ atoms covalently bonded together; net overall charge (+/-)

Formula Types

Empirical

Molecular

Structural

each diff element in subst. written in simplest form H2O2 --- HO Pb2(SO4)4 --- Pb(SO4)2 - PbSO

actual # of each diff element in subst.; H2O2

give relative manner in atoms are arranged in subst.; H—O—O—H

Ionic or Covalent ????

Ionic: metal + nonmetal joined together to form an ionic cmpd. by forming an ionic bond

Covalent: nonmetal + nonmetal joined together to form a covalent molecule by forming a covalent bond

pg58

COMPOUND

Binary: compound comprised of only 2 different elements

Magnesium Nitride

Name: second element name ends in -ide

Mg3N2 PCl3

Phosphorus Trichloride

IONIC CMPD

Regular

Irregular

1st: name metal -- 2nd: single nonmetal, name with -ide ending NaCl -- Sodium Chloride Ba3P2 -- Barium Phosphide 2nd: name of polyatomic group (pg 62)

AgNO3 -- Silver Nitrate

Metal elements w/ only one positive chargeMain group elements -- A columnsCol. 1A -- +1 Col. 2A -- +2 Col. 3A -- +3 Ag +1 Zn +2

Metal elements w/ more than one positive chargeTransistion elements -- B columns Metal use name w/ charge, or, derived name lowest -ous highest -ic

1st: name metal, charge -- 2nd: single nonmetal, name with -ide ending FeCl2 -- Iron II Chloride FeCl3 -- Iron III Chloride Ferrous ” Ferric ” 2nd: name of polyatomic group Co(NO2)2 -- Cobalt II Nitrite

CHEMICAL SYMBOLS

H; Sn; W; He --

First letter is always CAPITALIZED

Second letter, if present, always lower case

He not HE

symbols are of 1 or 2 letters

Na not NA

NOMENCLATURE & FORMULA WRITING

Important components to always keep in mind are:

1. Oxidation numbers 2. Which are “+” & “-” ions 3. Ionic/Covalent 4. Binary or higher 5. Metal > 1 charge

OXIDATION NUMBERS

1. “H” +1 except hydrides (-1)2. “O” –2 except peroxides (-1); w/ “F” (+2)

3. “F” Fluorine, always -14. Metal always “+” joined w/ Nonmetal always “-”

5. Metals 1st Col. +1 2nd Col. +2

Nonmetal “-” charge based on # moves to end of row

BINARY COMPOUNDSCmpds. containing 2 diff. elements

A. IONIC CMPDS:

1st : Name of element 2nd: Element name, ending

changed to “–ide”NaCl ___________ BaF2 ___________

Metal + Nonmetal

Fe+2 Cl-1 Fe+3 Cl-1

Fe1Cl2Fe1Cl3

Polyatomic Pattern -- Oxoanions

no “O” 1 - O 2 - O 3 - O 4-O -ide hypo-root-ite root-ite root-ate per-root-ate -I -IO -IO2 -IO3 -IO4

iodide hypoiodite iodite iodate periodateAcid

hydro-root-ic hypo-root-ous root-ous root-ic per-root-ic HI HIO HIO2 HIO3 HIO4

Hydroiodic Hypoiodous Iodous Iodic Periodic

see list“on-linesyllabus”

COVALENT MOLECULESSame pattern as Ionic Cmpds, but, use prefix to indicate # of each element present

PREFIXES:

mono: 1 di: 2 tri: 3 tetra: 4 penta: 5

hexa: 6 hepta: 7 octa: 8 nano: 9 deca: 10

B. COVALENT MOLECULES (CMPDS)

1st : Name of element 2nd: Element name, ending

changed to “–ide”

CO __________ N2O __________

Nonmetal + Nonmetal

prefix only ifsubscript # > 1

always use prefix, even if subscript only 1

CO CO2

Carbon Carbon

P2S5 __________

-ITE & -ATE ENDINGS

-ite & -ate ending indicates the presence of “oxygen”

-ite ending indicates 1 less “O” than –ate ending

-ate ending indicates 1 more “O” than –ite ending

MULTIPLE CHARGED METALSIRREGULAR METALS

Metals w/ 2 or more charges

Use: 1) Roman Numeral to indicate the charge 2) Derivative Name

Iron IIIron III

Copper ICopper II

FerrousFerric

CuprousCupric

-OUS lowest charge

-IC highest charge

FeO Fe2O3No subscripts

charge “O” –2= charge “Fe” +2

Iron II OxideFerrous Oxide

Fe2 O3

+3 -2

Charge on “Fe” = +3

Iron III OxideFerric Oxide

Fe O-2+2

ACID NAMING PATTERN

Based on the polyatomic ions “ate” & “ite” endings

No “O”

Hydro-

HCl Hydrochloric Acid

root-ic

H2S Hydrosulfuric Acid

H3P Hydrophosphoric Acid

Halogen Acid Pattern

F, Cl, Br, I

1 “O” 2 “O” 3 “O” 4 “O”

-ClO -ClO2-ClO3 -ClO4

Hypochlorite Chlorite Chlorate Perchlorate

Hypochlorous Acid

Chlorous Acid

Chloric Acid

Perchloric Acid

-ITE Change ending to “OUS”

-ATE Change ending to “IC”

HYDRATE : In a cmpd refers to WATER -- H2O

Calcium Sulfate Octahydrate

Ca SO4 . 8H2O

Beryllium Hydroxide

Be OH+2 -1

21 Be OH 2( )

Cu3(PO4)2

Copper Phosphate Ion

Metal w/ multiple charges (+1 or +2)

II

CO3 & 2

3CO

Carbon Trioxide Carbonate Ion

KFPotassium Fluoride

Sn(SO4)2Tin IV Sulfate Sn(+4) & SO4(-2): Added

subscripts(from the charges) are simplified inIonic Cmpds

Sn2(SO4)4

The charge on SO4 times the subscriptgives you the charge on Tin: 2 * |-2| = 4

Lead II Bicarbonate

Ammonium Silicate

FerricIron III

Dichromate

ZnO

charge P + charge O = -3 We know O-2 Then P must be +

PO3-3

P? + 3(O-2) = -3

P+3

P? = -3 - 3(O-2) P? = -3 – (-6)

? = +3

closer to F, more neg charge

EXCEPTIONS

Oxides Peroxides

H2O

Li2O

Na2O

K2O

Rb2O

Hydrogen

Lithium

Sodium

Potassium

Rubidium

DiWater

H2O2

Li2O2

Na2O2

K2O2

Rb2O2

O-2O-1 Hydride H-1

NiH2

Nickel II Hydride

NaH

Sodium Hydride

Exceptions