Ionic bonding Flashcards
ionic bonding is confined to solid materials consisting of a regular
array of oppositely charged ions extending throughout a giant lattice network
the most familiar ionic compound, NaCl, consists of a regular array of
sodium ions, Na+, and chloride ions, Cl-
in ionic compounds, the ions (relative closeness)
touch each other
in an ionic solid, there are …………………between the ions
strong electrostatic interactions
the ions are arranged in a way that the
electrostatic attractions between oppositely charged ions are greater than the electrostatic repulsions between ions with the same charge
electrostatic attractions between oppositely charged ions are………………than electrostatic repulsions between ions with the same charge
greater
when ions are present, the electrostatic interaction between them tends to be
dominant
the electrostatic interaction between ions is not
directional
the electrostatic interaction between ions is not directional: all that matters is the
distance between two ions, not their orientation with respect to one another
you can determine the strength of ionic bonding by calculating
the amount of energy required in one mole of solid to separate the ions to infinity (to the gas phase)
for ions of the same charge, the smaller the ions
the more energy is required to overcome the electrostatic interactions between the ions and to separate them
when comparing chemical values for ionic radii, you should make sure
all the data you are comparing comes from the same source, as different databases will have different values
typical properties for ionic compounds are (4 items)
- high melting temperatures
- brittleness
- poor electrical conductor when solid but good when molten
- often soluble in water
ionic compounds are brittle because
- is stress is applied, the layers of ions will slide over each other
- as ions of the same charge are now side by side, the repel one another
- the crystals break apart
generally, solid ionic compounds do not conduct electricity because
there are no delocalised electrons or ions which are free to move under the influence of an applied potential difference
molten ionic compounds are able to conduct electricity because
the ions are now mobile, and will migrate to the electrodes of opposite sign when a potential difference if applied
aqueous solutions of ionic compounds will/will not conduct electricity because
will, because the lattice breaks down into separate ions when the compound dissolves
