5.1 -5.3 Page 125 - 155
WHO CREATED THE PERIODIC TABLE?
https://www.youtube.com/watch?v=fPnwBITSmgU
DMITRI MENDELEEV 1834-1907
 Russian chemistry professor
 Wrote name of element & properties on
separate cards
 Arranged cards in order of increasing atomic
mass
 Also “grouped” elements by similar properties
SOME ELEMENTS
WERE MISSING
 Mendeleev postulated the existence of yet to be discovered
elements.
 Table included some irregularities
o Mendeleev thought irregularities were due to poor
measurements of atomic mass
HENRY MOSELEY
 English Scientist
 Arranged table according to Atomic Number rather
than Atomic Mass
 This took care of irregularities
 Moseley’s improvements gave us today’s Periodic
Table
REGIONS OF THE PERIODIC TABLE
MAIN BLOCK – properties vary symmetrically (the most predictable)
Hydrogen - H
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“sits” on top of the table
behaves unlike any other element
basis of acids
considered a family in itself
FAMILY CHARACTERISTICS
NOBLE GASES
 inert – unreactive, an element or compound that does not react
with others
 stable
 non- flammable
 They form monatomic (single atom) gases.
 full outer shells (this is why they are unreactive)
GROUP 1 ALKALI METALS
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explosive reactions with water – (stored in oil)
extremely unstable on their own
soft metal – cut with a knife like cheese
name derived from Arab word for “ashes”
outer shell has one electron
stable if it loses an electron
What are the ALKALI METALS?
GROUP 2 ALKALINE-EARTH METALS
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harder than alkali metals
more dense than alkali metals
stronger than alkali metals
outer shell has two electrons
stable if it loses two electrons
less reactive due to # of electrons in outer shell
forms a skin with oxide to protect itself
What are the ALKALINE-EARTH METALS?
GROUPS 3-12 TRANSITION METALS
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harder than alkaline-earth metals
more dense than alkaline-earth metals
stronger than alkaline-earth metals
outer most electrons in d orbitals
all conduct electricity, heat
EXCEPTION : Hg is the only non-solid metal
LANTHANIDES
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Shiny, metallic elements
Numbers 58 through 71
Outer electrons in f orbital
Uses- inside of televisions sets
ACTINIDES
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Metallic elements
Numbers 90 through 103
Unstable – nuclear decay
Best known – Uranium
GROUP 17 HALOGENS
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Combine with most metals to form salts
Halogen – Latin for salt-former
Most reactive non-metal
Outer shell one electron short of being full
Halogens gain an electron for stability
What are the HALOGENS?
OTHER MAIN BLOCK GROUPS
B
Al
 Named after element at top of column
 Outer shell has the same number of
electrons
 Forms the same charge ion
 Similar behavior in reactions
 Similar stability
Ga
In
Tl
What are the other families?
BORON FAMILY
CARBON FAMILY
NITROGEN FAMILY
OXYGEN FAMILY
4-2 TRENDS WITHIN THE PERIODIC TABLE
Definition
ION – an ion is an atom which has gained or lost electrons to obtain
stability.
Since Atoms would like to have a full outer shell they may get a full
shell by either gaining or losing electrons.
Example:
Lithium
SKETCH OF THE LITHIUM ATOM:
To become stable Lithium
gives up its electron in the
outer shell
Prior to losing the electron what is the charge of a Lithium atom?
+3 (protons) + -3(electrons) = 0
or NEUTRAL
What is charge of Lithium ion (after it has lost the electron)?
+3 (protons) + -2(electrons) = +1 charge
Definition
CATION – an ion which has lost an electron(s) to become stable, its
overall electrical charge is positive.
Another Example:
Fluorine
SKETCH THE FLUORINE ATOM:
9 protons surrounded by 2
electrons in the first shell
and 7 in the second shell.
To become stable Fluorine
gains an electron in the
outer shell
Prior to losing the electron what is the charge of a Fluorine atom?
+9 (protons) + -9(electrons) = 0
or NEUTRAL
What is charge of Fluorine ion (after it has gained the electron)?
+9 (protons) + -10(electrons) = -1 charge
Definition –
ANION – an ion which has gained an electron(s) to become stable, its
overall electrical charge is negative.
Definition –
IONIZATION ENERGY – the energy required to remove an electron
from the neutral atom – this is measured in the units of energy (Joules)
SIZE OF THE ATOM :
INCREASES DOWN A FAMILY
DECREASES FROM LEFT TO RIGHT
(counterintuitive)
DRAW ARROWS ALONG THE TOP AND LEFT SIDE TO INDICATE
WHICH DIRECTION THE SIZE OF THE ATOMS ARE INCREASING
INCREASING RADIUS
INCREASING IONIZATION ENERGY