ATOMS, MOLECULES,
& IONS
Dalton: atomic theory
Molecules & Compounds
Atomic Structure &
Weights
P. Table
CMPDS: formula, name
Molecule/Cmpd
Cmpd: metal + nonmetal
transfer of emetal lose & nonmetal gains
Molecule: nonmetal + nonmetal
share e= or un= sharing
Law Mass Conservation
Total mass not D in chem rxn.
- total mass reactants = total mass pdts
H2 + O2 -------> H2O
2 H2 + O2 ------> 2 H2O
1.0
16.0
2.0 + 16.0
2*2.0 + 32.0
2*18.0
2.0 + 32.0
34.0
= 18.0
36.0
=
36.0
Mass is neither created nor
destroyed, but changes form
Definite Composition
Law: cmpd composed of elements in a fixed ratio by weight
Fraction Mass: fraction each element contributes to total mass of cmpd
Fract.Mass  mass of each element
total mass cmpd.
% Mass: % mass each element contributes to total mass of cmpd
% mass = fraction mass * 100
Multiply Proportions
When 2 elements combine to give to diff. substances, the masses of
elements that form molecule can be expressed as a simple whole #
CO
43% C 57% O
CO2
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
Atomic Mass: relative ave mass of element including
% of all isotopes
Mass Number: atomic mass rounded to nearest whole number
# protons + # neutrons
Isotope: diff form of same element
diff # of neutrons
Greeks: 4 elements
earth - air - water - fire
Democritus - particles atomos
Newton
Dalton - atomic theory, 4 postulates
pg 42
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
Rutherford
Au foil
particles
p+, protons
n0, neutrons
e-, electrons
pg 48
e-: -1.602*10-19 C
p+: + 1.602*10-19 C
charge
“1+”
“0”
“1-”
mass
1
1
0
location
nucleus
nucleus
outside
p+ 1.0073 amu
n0 1.0087 amu
e- 5.486*10-4 amu
determine
element
isotope
chemistry
1836 e- =
1 p+ mass
ISOTOPE NOTATION
mass #
p+ + n0
p.table
atomic #
# p+
p.table
88
38
Sr
50
X
+/- charge
59
# n0
mass# - atomic#
28
Ni
What info
can you
get
Element:
Mass #:
p.table
Symbol:
# n0
Notation with 2 less e-’s
Atomic #:
31
Element: Phosphorus
Symbol:
This is element # , therefore, it is Atomic #
Mass #:
# n0
Write notation with 3 more e-’s
Now, try notation
for O-15
RELATIVE ATOMIC WEIGHT
•
NEON
3 Isotopes
20.1797
Isotope Mass
% Abundance
20Ne
19.9924356
90.48 %
21Ne
20.9938428
0.27 %
21.9913831
9.25 %
22Ne
20Ne
19.9924356 * 0.9048 = 18.08915573
21Ne
20.9938428 * 0.0027 = 0.056683376
22Ne
21.9913831 * 0.0925 = 2.034202937
+
20.18004204
ATOMIC MASS SCALE
1 amu = 1.66054*10-24 g
1 g = 6.02214*1023 amu
mole
Atomic Weight
H = 1.00794 = 1
particles
charge
p+, protons
“+”
n0, neutrons “0”
e-, electrons “-”
1 p+
0 n0
2 p+
2 n0
He = 4.0026 = 4
Co = 58.9332 = 59
mass
1
1
0
27 p+
32 n0
PERIODIC TABLE
families, series,
metal/nonmetal/metaloid
incr atomic #
last element not reactive;
complete filled e- shell
rows: periods/series
columns: families/groups
similar properties;
same # valence e-
ELEMENT CHARACTERISTICS
nonmetal
metal
No luster or shine
Not malleable
Not ductile
Forms molecules w/ each other
or other elements
Not conduct
20 elements
Can form “+” & “-” charges
Usually solids @ room temp
Shine w/ luster, metallic luster
Ductile: form into a wire,
stretch when pulled
Malleable: able to hammer (pound) into
shape, deform w/o breaking
Conducts heat & electricity
Always “+” charge
70% of elements
metalloid
Form alloys w/ other metals
Brass, Bronze
Properties similar to metals & nonmetals
Cu + Zn
Cu + Sn
Conduct 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 + nonmetal
cation(+) anion(-)
Binary - 2 element cmpd; + metal & - non
Na+1Cl-1
Mg+2O-2
NaCl
MgO
Sodium Chloride
Magnesium Oxide
NOTICE:
= opp charges, &
diff charges
Na+1O-2
Mg+2Cl-1
Na2O
MgCl2
Sodium Oxide
Magnesium Chloride
REVIEW: Structure of an Atom
3 subatomic particles:
p+; no; ee- --> chemistry (E)
p+ --> element
no --> isotope
Z: atomic number; # p+; i.d. element
A: mass number; p+ + no
N: # no; A - Z
Atomic Symbol
Isotope Notation
A ch arg e
Z XN
FORMS:
39 K
19
Potassium - 39
39 K
19 20
K - 39
39 K 1
19 20
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
# p+ > # e# p+ < # e-
Anion: - charged
“+” charge
“-” charge
same element, same # p+, only change # e-
# p+ = # eno charge to atom
magnitude 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
Diatomics
H2 -- 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
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
Structural
give relative manner in atoms are arranged in subst.;
H—O—O—H
pg58
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
COMPOUND
Binary: compound comprised of only 2 different elements
Name: second element name ends in -ide
Mg3N2
Magnesium Nitride
PCl3
Phosphorus Trichloride
IONIC CMPD
Regular Metal elements w/ only one positive charge
Main group elements -- A columns
Col. 1A -- +1
Col. 2A -- +2 Col. 3A -- +3
Ag +1
Zn +2
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
Irregular Metal elements w/ more than one positive charge
Transistion 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
He
not
HE
Na
not
NA
H; Sn; W; He -- symbols are of 1 or 2 letters
First letter is always CAPITALIZED
Second letter, if present, always
lower case
NOMENCLATURE & FORMULA WRITING
Important components to always keep in mind are:
1. Oxidation numbers
3. Ionic/Covalent
5. Metal > 1 charge
2. Which are “+” & “-” ions
4. Binary or higher
OXIDATION NUMBERS
1. “H” +1 except hydrides (-1)
2. “O” –2 except peroxides (-1); w/ “F” (+2)
3. “F” Fluorine, always -1
4. Metal always “+” joined w/ Nonmetal always “-”
5. Metals 1st Col. +1 Nonmetal “-” charge based on
# moves to end of row
2nd Col. +2
BINARY COMPOUNDS
Cmpds. containing 2 diff. elements
A. IONIC CMPDS: Metal + Nonmetal
1st : Name of element
NaCl ___________
Fe
+2
Cl
Fe1Cl2
-1
2nd: Element name, ending
changed to “–ide”
BaF2 ___________
Fe+3 Cl-1
Fe1Cl3
see list
“on-line
syllabus”
no “O”
-ide
-I
iodide
Polyatomic Pattern -- Oxoanions
1-O
hypo-root-ite
-IO
hypoiodite
2-O
root-ite
-IO2
iodite
3-O
root-ate
-IO3
iodate
4-O
per-root-ate
-IO4
periodate
Acid
hydro-root-ic
HI
Hydroiodic
hypo-root-ous
HIO
Hypoiodous
root-ous
HIO2
Iodous
root-ic
HIO3
Iodic
per-root-ic
HIO4
Periodic
COVALENT MOLECULES
Same pattern as Ionic Cmpds, but,
use prefix to indicate # of each element present
PREFIXES:
mono: 1
di: 2
hexa: 6
hepta: 7
tri: 3
octa: 8
tetra: 4
nano: 9
penta: 5
deca: 10
B. COVALENT MOLECULES (CMPDS)
Nonmetal + Nonmetal
1st : Name
of element
prefix only if
subscript # > 1
CO __________
CO
Carbon
P2S5 __________
2nd: Element name, ending
changed to “–ide”
always use prefix, even
if subscript only 1
N2O __________
CO2
Carbon
-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 METALS
IRREGULAR METALS
Metals w/ 2 or more charges
Use: 1) Roman Numeral to indicate the charge
2) Derivative Name
Iron II
Iron III
Ferrous
Ferric
Copper I
Copper II
-OUS lowest charge
-IC highest charge
Cuprous
Cupric
FeO
Fe2O3
No subscripts
+2
-2
Fe O
charge “O” –2
= charge “Fe” +2
Iron II Oxide
Ferrous Oxide
+3
-2
Fe2 O3
Charge on “Fe” = +3
Iron III Oxide
Ferric Oxide
ACID NAMING PATTERN
Based on the polyatomic ions “ate” & “ite” endings
No “O”
Hydro- root-ic
HCl Hydrochloric Acid
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
Chlorite
Chlorate
Perchlorate
Chlorous
Acid
Chloric
Acid
Perchloric
Acid
Hypochlorite
Hypochlorous
Acid
-ITE
-ATE
Change ending to “OUS”
Change ending to “IC”
HYDRATE : In a cmpd refers to WATER -- H2O
Calcium Sulfate Octahydrate
Ca SO4 . 8H2O
Beryllium Hydroxide
+2 -1
Be 1 OH
2
Cu3(PO4)2
Be(OH)2
Metal w/ multiple charges
(+1 or +2)
Copper II Phosphate Ion
CO3
Carbon Trioxide
&
CO2
3
Carbonate Ion
KF Potassium Fluoride
Sn(SO4)2 Tin IV Sulfate
Sn(+4)
Sn2(SO4)4
& SO4(-2): Added subscripts
The charge on SO4 times the subscript (from the charges) are simplified in
gives you the charge on Tin: 2 * |-2| = 4 Ionic Cmpds
Lead II Bicarbonate
Ammonium Silicate
ZnO
Ferric Dichromate
Iron III
PO3
-3
closer to F, more
neg charge
charge P + charge O = -3
-2
P? + 3(O ) = -3
We know O-2
-2
P? = -3 - 3(O )
P
+3
Then P must be +
P? = -3 – (-6)
? = +3
Exceptions
Oxides
O
EXCEPTIONS
-2
Peroxides
H2O
Di Hydrogen
Water
H2O2
Li2O
Lithium
Li2O2
Na2O
Sodium
Na2O2
K2O
Potassium
K2O2
Rb2O
Rubidium
Rb2O2
O
-1
Hydride
H
-1
NiH2
Nickel II Hydride
NaH
Sodium Hydride