Ionic bond Flashcards
common ionic compounds in daily life
sodium chloride NaCl table salt
sodium bicarbonate NaHCO3 baking soda
sodium hydroxide NaOH lye drain cleaner
magnesium sulfate MgSO4 Epsom salt
sodium hypochlorite NaOCI bleach
what is octet rule
Atoms of elements tend to combine in such a way that they have eight
electrons in their outermost/valence electron shell (two electrons for
period 1 elements), giving them the same electron arrangement as a
noble gas (octet structure).
how do atoms obtain octet structure
They achieve this by either transferring electrons or sharing electrons
how are cations formed
Metal atoms lose electrons to become
cations (positive ions).
how are anions formed
Non-metal atoms gain electrons to become
anions (negative ions).
what determines the number of electrons gained or lost
The number of electrons lost or gained is determined by the electron
configuration of the atom.
what holds the positively and negatively
charged ions together
The positively and negatively
charged ions are held together in a
giant lattice
what is a giant lattice
It is a regular 3D
arrangement with infinite ions - formed
by many strong ionic bonds.
what is ionic bond
Strong electrostatic force of attractions
between oppositely charged ions.
naming of ionic compounds
● When naming an ionic compound, cation should be
named first and followed by anion.
● No prefix needed to indicate the number of ions in
the compound.
● The charge of transition metal cations (several
possible charges) should be shown as a roman
numeral in a bracket.
what does the physical properties of ionic compounds depend on
(a) type of structure,
(b) the type of constituent species, and
(c) the type (the strength) of attraction between constituent species
Melting point and boiling point of ionic compounds
● Ionic compounds are solids under ambient conditions (25 °C and 1 atm).
● Strong electrostatic force of attractions between the oppositely charged ions
(ionic bond) in its lattice
● Large amount of heat energy is required to break the many strong bonds.
what is volatility
Tendency of a substance to vaporize.
volatility of ionic compounds
Ionic compounds are considered as being
non-volatile
○ large amount of energy needed to break
the strong ionic bonds in lattice
hardness of ionic compounds
brittle and hard
If layers of ions slip against each other, ions with the same charge come up
against each other – like charges repel and break up the crystal
electrical conductivity of ionic compounds
Movement of charges (e.g. electrons, ions) is needed to
conduct electricity.
● Solid ionic compounds do not conduct electricity -
ions are held firmly (fixed) in the lattice.
● Molten/ liquid ionic
compounds conduct
electricity.
● Mobile ions move to
conduct electricity
● Aqueous ionic
compounds (dissolved
in water) conduct
electricity.
● Mobile ions move to
conduct electricity.
solubility rules (1)
All compounds with group 1 metal ions (e.g. Na+, K+) and ammonium ions (NH4+) are soluble.
solubility rules (2)
All nitrates (NO3-) and hydrogencarbonates (HCO3-)
are soluble.
solubility rules (3)
All carbonates (CO32-) and phosphates (PO43-) are
insoluble except those mentioned in (1), group 1 metal ions
solubility rules (4)
All hydroxides (OH-) are insoluble except those
mentioned in (1), Ba(OH)2and Ca(OH)2
(sparingly soluble). It is an aqueous solution when it is
in the form of limewater. However, when it is formed during
reactions, it exists as an insoluble compound.
solubility rules (5)
All sulphates (SO42-) are soluble except CaSO4 , BaSO4 ,
PbSO4 , Ag2SO4 .
solubility rules (6)
All halides (Cl-, Br-, I-, general form: X-) are soluble
except PbX2 and AgX.
what are ionic equations
Equations that only show the chemical species that have participated in the reaction (such as ions and molecules).
what are spectator ions
Ions that are chemically unchanged for the entire process are called spectator ions - they can be removed from the equation.
what is precipitation
When two aqueous ionic solutions are mixed together, if an insoluble ionic compound is produced, a precipitate will be formed. It is also known as the double replacement reaction
what happens during the process of precipitation
During the process, the cations and the anions of the two solutions are exchanged.
what is the precipitate
it is the insoluble ionic compound, it settles and falls to the bottom of the solution
what is supernate
it is a solution which remains above a precipitate
precipitation of silver chloride
When colourless silver nitrate solution is added to colourless sodium chloride solution, white precipitate of silver chloride is produced.
Overall equation:
AgNO3 (aq) + NaCl (aq) → AgCl(s) + NaNO3 (aq)
Ionic equation:
Ag+ (aq) + Cl-(aq) → AgCl(s)
