THE
PERIODIC
LAW
I. HISTORY OF THE
PERIODIC TABLE
A. 1860- FIRST INTERNATIONAL
CONGRESS OF CHEMISTS
1. ITALIAN CHEMIST STANISLAO
CANIZZARO PRESENTS A
CONVINCING METHOD FOR
ACCURATELY MEASURING
RELATIVE ATOMIC MASSES.
2. DMITRI MENDELEEV
INCLUDES NEW ATOMIC
MASSES IN A CHEMISTRY
TEXTBOOK.
3. MENDELEEV NOTICED A
PERIODIC TREND WHEN HE
ARRANGED ELEMENTS
ACCORDING TO ATOMIC
MASS.
B. 1869- MENDELEEV
PUBLISHES HIS FIRST
PERIODIC TABLE
WHERE ELEMENTS
ARE ARRANGED
ACCORDING TO
ATOMIC MASS.
C. 1871- MENDELEEV
PREDICTS EXISTENCE
AND PROPERTIES OF
SEVERAL “MISSING”
ELEMENTS ON HIS
PERIODIC TABLE.
II. MOSELEY AND THE
PERIODIC LAW
A. 1911- HENRY MOSELEY
ARRANGED ELEMENTS
ACCORDING TO ATOMIC
NUMBER USING LINE
SPECTRA.
1. THIS HELPED DEFINE
ATOMIC NUMBER
B. THE PERIODIC
LAW
1. THE PHYSICAL AND
CHEMICAL PROPERTIES
OF THE ELEMENTS ARE
PERIODIC FUNCTIONS
OF THEIR ATOMIC
NUMBERS
III. THE MODERN
PERIODIC TABLE
A. AN ARRANGEMENT OF THE
ELEMENTS IN ORDER OF
THEIR ATOMIC NUMBERS TO
THAT ELEMENTS WITH
SIMILAR PROPERTIES FALL
IN THE SAME COLUMN OR
GROUP
B. THE NOBLE
GASES
1. 1894- JOHN WILLIAM STRUTT
(LORD RAYLEIGH)AND SIR
WILLIAM RAMSAY
DISCOVERED ARGON
2. 1895- RAMSAY
DEMONSTRATED THAT HELIUM
EXISTS AS AN ELEMENT ON
EARTH
3. 1898- RAMSAY
PROPOSES NEW GROUP,
NOBLE GASES AND
DISCOVERS KRYPTON
AND XENON
4. 1900- FRIEDRICH ERNST
DORN DISCOVERS
RADON
C. THE LANTHINIDES
1. EARLY 1900’SLANTHANIDES
UNDERSTOOD.
2. SO SIMILAR IN
PROPERTIES, THEY ARE
HARD TO SEPARATE
D. THE ACTINIDES
1. EARLY 1900’S- ACTINIDES
FIRST DISCOVERED
2. MOST ARE RADIOACTIVE
3. MANY ARE MAN MADE
IV. ELECTRON
CONFIGURATION AND THE
PERIODIC TABLE
A. PERIODS AND BLOCKS OF
THE PERIODIC TABLE
1. PERIODS- HORIZONTAL
ROWS IN THE PERIODIC
TABLE
2. 1ST PERIOD: 1s SUBLEVEL FILLED, 2
ELEMENTS
3. 2ND PERIOD: 2s AND 2p SUBLEVELS
FILLED, 8 ELEMENTS
4. 3RD PERIOD: 3s AND 3p SUBLEVELS
FILLED, 8 ELEMENTS
5. 4TH AND 5TH PERIODS: 3d AND 4d
SUBLEVELS FILLED, 18 ELEMENTS
6. 6TH AND 7TH PERIODS: 4f AND 5f
SUBLEVELS FILLED, 32 ELEMENTS
B. THE s-BLOCK ELEMENTS:
GROUPS 1 AND 2
1. CHEMICALLY REACTIVE
METALS
2. GROUP 1 VALENCE LEVEL
HAS A SINGLE s ELECTRON
3. GROUP 2 VALENCE LEVEL
HAS 2 s ELECTRONS
4. GROUP 1: ALKALI METALS
a. SILVERY
b. SOFT ENOUGH TO CUT
WITH A KNIFE
c. TOO REACTIVE TO BE
FOUND FREE IN NATURE
d. GOING DOWN THE
COLUMN, MELTING POINT
DECREASES
5. GROUP 2: ALKALINE
EARTH METALS
a. HARDER, DENSER,
AND STRONGER THAN
ALKALI METALS
b. ALSO TOO REACTIVE
TO BE FOUND FREE IN
NATURE
C. HYDROGEN AND
HELIUM
1. HYDROGEN HAS THE
SAME ELECTRON
CONFIGURATION AS
GROUP 1 ELEMENTS,
BUT DOES NOT SHARE
THEIR PROPERTIES
2. HELIUM HAS THE SAME
ELECTRON CONFIGURATION
AS GROUP 2 ELEMENTS.
3. HOWEVER, WITH 2
ELECTRON IN THE HIGHEST
ENERGY LEVEL HELIUM IS
STABLE LIKE THE GROUP 18
ELEMENTS (NOBLE GASES).
D. THE d-BLOCK
ELEMENTS: GROUPS 3-12
1. SUBLEVELS FILLED IN THE
ORDER 4s3d.
2. REFERRED TO AS TRANSITION
ELEMENTS.
3. GOOD CONDUCTORS OF
ELECTRICITY AND LUSTROUS
4. LESS REACTIVE THAN GROUPS
1&2.
E. THE p-BLOCK
ELEMENTS: GROUPS 13-18
1. EXCLUDES HELIUM
2. ALONG WITH THE sBLOCK ELEMENTS ARE
KNOWN AS THE MAIN
GROUP ELEMENTS
3. INCLUDES NONMETALS,
METALLOIDS, AND METALS.
4. HALOGENS (GROUP 17) ARE
THE MOST REACTIVE
NONMETALS
5. METALLOIDS ARE
ELEMENTS WITH PROPERTIES
OF BOTH METALS AND
NONMETALS
F. THE f-BLOCK ELEMENTS:
LANTHANIDES AND
ACTINIDES
1. LANTHANIDES ARE SHINY
METALS AND SIMILAR IN
REACTIVITY TO GROUP 2
ELEMENTS.
2. ACTINIDES ARE ALL
RADIOACTIVE, 4 ARE NATURAL
AND THE REMAINING 10 ARE
MAN MADE.
V. ELECTRON
CONFIGURATION
AND PERIODIC
PROPERTIES
A. ATOMIC RADII
1. ONE-HALF THE
DISTANCE BETWEEN
THE NUCLEI OF
IDENTICAL ATOMS
THAT ARE BONDED
TOGETHER
2. PERIOD TRENDS
a. LEFT TO RIGHT ATOMIC
RADII DECREASE.
b. CAUSED BY THE
INCREASING POSITIVE
CHARGE OF THE
NUCLEUS.
3. GROUP TRENDS
a. THE RADII OF THE MAIN
GROUP ELEMENTS
INCREASE FROM TOP TO
BOTTOM.
b. THE OTHER ELEMENTS DO
NOT FOLLOW THIS TREND
AS WELL.
B. IONIZATION ENERGY
1. IONIZATION IS ANY PROCESS
THAT RESULTS IN THE
FORMATION OF AN ION.
2. IONIZATION ENERGY IS THE
AMOUNT OF ENERGY
NECESSARY TO REMOVE ONE
ELECTRON FROM A NEUTRAL
ATOM OF AN ELEMENT
3. PERIODIC TRENDS
a. IONIZATION ENERGIES
OF THE MAIN GROUP
ELEMENTS INCREASE
FROM LEFT TO RIGHT.
4. GROUP TRENDS
a. AMONG THE MAIN
GROUP ELEMENTS,
IONIZATION ENERGIES
GENERALLY DECREASE
DOWN THE GROUPS.
5. REMOVING ELECTRONS
FROM POSITIVE IONS
a. THE
ENERGIES FOR
REMOVAL OF ADDITIONAL
ELECTRONS FROM AN ION
ND
RD
ARE CALLED 2 , 3 , ETC.
IONIZATION ENERGIES
C. ELECTRON AFFINITY
1. THE ENERGY CHANGE THAT
OCCURS WHEN AN ELECTRON
IS ACQUIRED BY A NEUTRAL
ATOM
2. MOST ATOMS RELEASE
ENERGY WHEN THEY ACQUIRE
AN ELECTRON
3. PERIOD TRENDS
a. ELECTRON AFFINITY
INCREASES FROM
LEFT TO RIGHT
ACROSS THE pBLOCK.
4. GROUP TRENDS
a. ELECTRON
AFFINITIES
DECREASE FROM
TOP TO BOTTOM.
5. ADDING ELECTRONS
TO NEGATIVE IONS
a.
ND
2
ELECTRON
AFFINITIES ARE ALL
POSITIVE BECAUSE IT
IS MORE DIFFICULT TO
ADD A SECOND
ELECTRON.
D. IONIC RADII
1. CATION- POSITIVE ION,
ELEMENT LOSES
ELECTRON(S).
2. ANION- NEGATIVE ION,
ELEMENT GAINS
ELECTRON(S).
3. PERIOD TRENDS
a. CATIONIC RADII
DECREASE FROM LEFT TO
RIGHT.
b. ANIONIC RADII
DECREASE FROM LEFT TO
RIGHT.
4. GROUP TRENDS
a. FROM TOP TO
BOTTOM IONIC
RADII INCREAESE.
E. VALENCE
ELECTRONS
1. THE ELECTRONS AVAILABLE
TO BE LOST, GAINED, OR
SHARED IN THE FORMATION OF
CHEMICAL COMPOUNDS
2. GROUP 1 & 2 HAVE 1 AND 2
VALENCE ELECTRONS
RESPECTIVELY.
3. GROUPS 13-18
HAVE A NUMBER
OF VALENCE
ELECTRONS EQUAL
TO THE GROUP
NUMBER MINUS 10.
F. ELECTRONEGATIVITY
1. A MEASURE OF THE ABILITY OF
AN ATOM IN A CHEMICAL
COMPOUND TO ATTRACT
ELECTRONS
2. FLUORINE IS ARRIBITRARILY
ASSIGNED AN
ELECTRONEGATIVITY OF 4.0
3. PERIOD TRENDS
a. EN INCREASES FROM
LEFT TO RIGHT WITH
SOME EXCEPTIONS.
4. GROUP TRENDS
a. EN DECREASES
FROM TOP TO
BOTTOM.
G. PERIODIC PROPERTIES OF
THE d- AND f-BLOCK
ELEMENTS
1. ATOMIC RADII
a. d-BLOCK: DECREASE
ACROSS PERIODS
b. f-BLOCK: IRREGULAR
PATTERN
2. IONIZATION ENERGY
a. INCREASES ACROSS
PERIODS
b. INCREASES DOWN
EACH GROUP
3. ION FORMATION AND
IONIC RADII
1. ELECTRONS ARE
REMOVED IN EXACTLY
THE REVERSE ORDER
GIVEN BY THE ELECTRON
CONFIGURATION
NOTATION
4. ELECTRONEGATIVITY
a. d-BLOCK ALL HAVE EN
BETWEEN 1.1 AND 2.54
b. d-BLOCK EN INCREASES
WITH DECREASING ATOMIC
RADII.
c. f-BLOCK ELEMENTS ALL
HAVE SIMILAR EN RANGING
FROM 1.1 TO 1.5.