The Periodic Table!!!!
3.1 The Periodic Table
• History
• Organization
• Electron arrangement & valence energy
level
Dmitri Mendeleev
• 1834-1907; sequenced known elements in
order of increasing atomic mass
• Elements with similar properties in same
column.
• Called Periodic Table because it highlighted
the repeated (periodic) patterns of
properties.
Periodic Law
• Chemical & physical properties of the
elements repeat in a regular, periodic
pattern when arranged by atomic number
• This is the basis for the modern periodic
table – arranged by atomic number.
The Modern Periodic Table
• Using the information in your data booklet,
complete the periodic table worksheet.
• Be sure to include a legend on your
worksheet.
Metalloids
Alkali metals (not H)
Alkaline earth metals
Transition metals
Halogens
Noble gases
Inner transition
IA
VIIA
G IIA
IIIA IVA VA VIA VIIA
L
G
GG GG
GG
L G
G
G
G
For more lessons, visit
www.chalkbored.com
• Group Names:
– Two systems: Old & New
• Old: Roman numerals with either A or B
• New: Integers 1-18 from left to right
• Group VA = Group 15
• Alkali Metals:
– Group 1
– Soft, light, reactive metals
• Alkaline Earth Metals:
– Group 2
– Harder, denser, and stronger than alkali metals
• Transition Metals:
– Group 3-12
– Form positive ions, reactive, make coloured
compounds
• Metalloids:
– On staircase between metals and non-metals
– Exhibits properties of both
• Halogens:
– Group 17; Reactive non-metals
– Electron deficient and readily share electrons
with other elements
• Noble Gases:
– Group 18
– Do not react chemically with other materials
and cannot be absorbed
– Valence shell full
The Periodic Table & Electrons
• Periodic trends are linked to the way
electrons fill energy levels.
• Remember that for each proton there is one
electron in an atom, therefore as the atomic
number increases, so does the number of
electrons.
• To understand trends, we use the BohrRutherford Model of the atom.
The Bohr-Rutherford Model
• Electrons in energy levels
• 2 in first level
• 8 in other levels
• What element is this?
• Sodium, Na
• Group Related Pattern:
– All the elements in a group have the same number
of valence electrons.
– The old number system – The roman numeral is the
same as the number of valence electrons.
– The new system – The last digit of the number is
the number of valence electrons.
• Period-Related Pattern
Period Number = Number of Energy Levels
3.2 Physical Properties
•
•
•
•
Ionization energy
Electronegativity
Atomic Radii
Ionic Radii
• Across period 3 & down group 1 & 17
More Trends – Worksheet
• Ionization Energy: The energy required to
remove one valence electron from an atom.
• Electronegativity: How strongly an atom
attracts the electrons in a covalent bond
• Atomic Radius:The distance from the nucleus
to the valence electron shell of an atom
• Ionic Radius: The distance from the nucleus
to the valence electron shell of an ion
Ionization energy vs. atomic number
He
Ionization energy (kJ/mol)
2500
Ne
2000
Ar
F
1500
N
H
Cl
C
Be
1000
O
P S
B
500
Mg Si
Al
Li
Ca
Na
K
0
0
2
4
6
8
10
12
Element
14
16
18
20
Ionization Energy Trend
Electronegativity Trend
Atomic radius vs. atomic number
Atomic Radius (pm)
250
K
200
Na
Li
150
Mg
Al Si
Be
100
Ca
P S Cl
B C N
O F
Ar
Ne
50
H
0
0
He
2
4
6
8
10
12
Element
14
16
18
20
Atomic Radius & Ionic Radius
http://www.mhhe.com/physsci/chemistry/esse
ntialchemistry/flash/atomic4.swf
Ionic Radius Trend
3.3 Chemical Properties
• Group Properties:
–
–
–
–
Alkali metals with water
Alkali metals with halogens
Halogens with water
Halogens with halide ions
• Oxides of period 3 properties
– Ionic vs. covalent bonding nature
– Basic vs. acidic nature
– Industrial processes
Alkali metals with H2O
• M + H2O  MOH + H2
• Trend:Very reactive; increasing down group
• Observations:
– Highly exothermic – heat & light
– Fizzing of hydrogen gas formed
– Video
Alkali Metals with Halogens
• M + X2  MX
• React in 1:1 ratio
Halogens with H2O
• Reactivity decreases down group because
electronegativity and oxidizing power
decreases down group; electrons farther
from nucleus and are shielded
• Halogens General Video
Halogen and halide ions
Higher Halogen displaces lower halogen from salt;
never other way around!
•
•
•
•
•
•
Cl2 + I-  Cl- + I2
Cl2 + Br-  Cl- + Br2
Br2 + I-  Br- + I2
Br2 + Cl-  No rxn
I2 + Cl-  No rxn
I2 + Br-  No rxn
Halogen and metal
• Make salts with halide ion
• Salts are usually white in colour and soluble
in water creating colourless solutions
• Common insoluble halides: silver and lead
Things to Know:
• Ionic compound– attraction of ions creates
bond
• Covalent compound – shared electrons
create bond
• Polar Covalent – a covalent bond where
electrons are not shared equally creating
positive and negative “ends” on the bond
• Acidic – having a pH of less than 7; H+
• Basic – having a pH of more than 7; OH
Oxides:
• Compounds containing at least one oxygen
atom
• Bonded with metal: ionic compound &
basic
• Bonded with non-metal: polar covalent
compound; polarity decreasing across
period & acidic (increasing across period)
• **aluminum oxide is amphoteric – reacts
with acid and base**
Oxide + H2O Reactions
• Na2O(s) + H2O(l)  2Na+(aq)+ 2OH-(aq)
• MgO + H2O → Mg(OH)2
• P4O10(s) + 6H2O(l)  4H+(aq) + 4H2PO4-(aq)
• SO3(s) + H2O  H+(aq) + HSO4-(aq)
Another MgO rxn:
MgO(s) + 2HCl(aq)  Mg2+(aq) + 2Cl-(aq)