Bonds
Ionic –
•Bond formed due to a difference in charge
– Loss or gain of an electron
•Usually forms between a metal and a
nonmetal
Bonds
Covalent –
•Bond formed from two atoms sharing an
electron
•Commonly found in “organic” compounds
(with H, C, and O, among others)
Dmitri Mendeleev
• Order elements by atomic mass
1834 - 1907
• Periodic Law – When the elements are
arranged in order of increasing relative mass,
certain sets of properties recur periodically
• used pattern to predict properties of
undiscovered elements
Periodic Table Pattern
nm H2O
a/b
H
1
H2
m Li2O m/nm BeOnm B2O3 nm CO2 nm N2O5 nm
O2 nm OF2
Li b
Be a/b B a
C a N a
O
F
7 LiH 9 BeH2 11 ( BH3)n 12 CH4 14 NH3 16 H2O 19 HF
left  right across a row (period) increasing atomic mass (not relative mass);
organized based on their activity and properties
Periodic Table Pattern
nm H2O
a/b
H
1
H2
m Li2O m/nm BeOnm B2O3 nm CO2 nm N2O5 nm
O2 nm OF2
Li b
Be a/b B a
C a N a
O
F
7 LiH 9 BeH2 11 ( BH3)n 12 CH4 14 NH3 16 H2O 19 HF
m Na2O m MgO m Al2O3 nm/m SiO2nm P4O10nm SO3 nm Cl2O7
Na b Mg b Al a/b Si a P a
S a Cl a
23 NaH24 MgH2 27 (AlH3) 28 SiH4 31 PH3 32 H2S 35.5 HCl
up  down column; similar properties; how the elements react with H and O
• some gaps were left in table for undiscovered elements; properties
of these elements were predicted.
PERIODIC TABLE
Non-metals
Metals
Metalloids
7
PROPERTIES OF
METALS & NON-METALS
Metals
Non-metals
• Mostly solid
• Can be solid, liquid or gas
• Have shiny appearance
• Have dull appearance
• Good conductors of
heat & electricity
• Poor conductors of heat
& electricity
• Malleable & ductile
• Brittle (if solid)
• Lose electrons
• Gain or share electrons
8
Metals
Non-metals
METALLOIDS
 Metalloids are elements
that possess some
properties of metals and
some of non-metals.
 The most important
metalloids are silicon (Si)
and germanium (Ge)
which are used extensively
in computer chips.
10
Metalloids
Properties of Silicon
shiny
conducts electricity
brittle
PERIODIC TABLE
Metallic
Metallic character
character decreases
increases going down
acrossaagroup
period.
Least metallic
Most metallic
element
elements
F
Cs
Fr
12
PERIODIC TABLE
 Seven elements exist as diatomic molecules.
 All others exist as monatomic (single atom).
13
PERIODS & GROUPS

 The
Elements
periodic
in the
table
same
is composed
family have
of periods
similar (rows)
properties,
and
and areorcommonly
referred to by their traditional
groups
families (columns).
names.
14
PERIODS & GROUPS
 Group
The group
Elements
Alkali
Noble
Halogens
gases
metals
2 elements
in
are
ofare
groups
metals
the
areun-reactive
most
soft
are
1-2
inmetals
called
reactive
between
and gases
13-18
alkaline-earth
that
nonmetals,
the
are
that
are
main
very
referred
aregroup
commonly
reactive.
and
metals.
to
occur
as
main-group
used
in
These
elements
nature
in
metals
light
are
only
or
bulbs.
called
are
as
representative
compounds.
less
transition
reactivewith
than
metals.
groups.
alkali
metals.
They
often
react
explosively
other
elements.
15
Pick a group
• Alkali metals
• Alkaline earth
metals
• Transition Metals
• Metalloids
• Halogens
• Noble Gasses
• Name of Group
• Elements in the
group
• Properties of the
elements in the
group
• Bonds usually
formed
• Reaction to fire