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Chemistry - Ionic Bonding - Ch 7 (Alloys (they are mixtures of two or more…
Chemistry - Ionic Bonding - Ch 7
To lose or to gain? :question:
depend on valence electrons
eg. Magnesium loses two electrons - ion form is Mg 2+ :warning:
cation = positively charged
anion = negatively charged
to fulfil the octet rule
ionic compound
neutrally charged compound composed of anions and cations
Properties
crystalline solids
at room temp
high
melthing
points
when
dissolved in water
it conducts
electrical current
brittle
- force push like charges together and they
repel
resulting in breaking into pieces
coordination number
the
number
of
ions of opposite charge
that surround each ion in a crystal
eg. the coordination no. of Na+ in NaCl is 6 because one Na+ has 6 Cl- ions
ionic bond
the electrostatic forces that hold ions together in an ionic compound
formula units
it is the lowest whole-number ratio of ions in an ionic compound
chemical formula
it shows the number of atoms of each element and the smallest representatice unit of a substance
Metal
Properties
sea of electrons
so electrons can move freely in the metal
conductivity of electric current
a sea of
drifting v. electrons insulates
the
cations
from each other
ductile and malleable
the valence electrons of a pure metal can be modeled as a
sea of electrons
metallic bonds
are the
forces of attraction
between the
free floating v. electrons
and the
positively charged metal ions
crystalline structure
Alloys
they are mixtures of two or more elements and at least one is a metal :
they are important because their properties are superior to those of their own component element :warning:
eg. steriling silver - 92% silver and Copper - jewelery
eg. Stainless steel - Iron, Carbon, Nickel and Cr - corrosion resitance
eg. cast iron