chemical bonding, structure and physical properties of substances Flashcards
where is ionic bonding formed
between metal and non-metal atoms
ionic bonding definition
strong electrostatic attraction between positive and negative ions
structure of ionic bonding
giant ionic structure
what does the ionic bonding structure consist of?
continuously repeating 3-dimensional lattice of positive and negative ions
melting and boiling point of ionic compounds
high melting, boiling point.
explanation: large amount of heat energy is needed to break the strong ionic bonds.
electrical conductivity of ionic compounds
conductor of electricity in molten and aqueous state.
explanation: in solid state, the ions are not free-moving. in molten or aqueous state, the ions are free moving and hence can conduct electricity.
solubility (in water/organic solvent) in ionic compounds
soluble in water, insoluble in organic solvents
where is covalent bonding formed?
between non-metal atoms
definition of covalent bonds
strong bond that is formed by the sharing of electrons
one pair of shared electrons is represented by ‘—‘. what is this known as
single covalent bond
what is simple covalent? give examples
covalent bonds among few atoms, H2, H2O, NH3, CH4, CO2
what is giant covalent? give examples
covalent bonds among large number of atoms. diamond, silicon, graphite.
what does the simple covalent structure consist of?
many molecules
what are the molecules in simple covalent substances attracted together by?
weak intermolecular forces
within each molecule, what are between atoms in simple covalent bonding?
strong covalent bonds
what is the structure of simple covalent substances known as?
simple covalent structure
melting and boiling point of simple covalent substances
low melting and boiling point
explanation: small amount of heat energy is needed to break the weak intermolecular forces
note** when melting or boiling simple covalent substances we are breaking the weak intermolecular forces and not the covalent bond between the atoms.
electrical conductivity of simple covalent substances, explain
non-conductor of electricity in any states
explanation: there are no free-moving electrons to conduct electricity
solubility of simple covalent substances
insoluble in water, soluble in organic solvents
what does the structure of giant covalent substances consist of
it consists of atoms forming covalent bonds throughout the entire structure
what is the structure of giant covalent substances known as?
giant covalent structure
examples of giant covalent substances
diamond, graphite, silicon, silicon dioxide
in the structure of diamond, each carbon atom form covalent bond with how many other carbon atoms throughout?
4
what arrangement/shape does the bonding between atoms in diamond result in
tetrahedral arrangement/shape
melting and boiling point of diamond
high melting and boiling point
explanation: large amount of heat energy is needed to break the strong covalent bonds
electrical conductivity of diamond
does not conduct electricity
explanation: there are no free-moving (mobile) electrons to conduct electricity. (each carbon atom in diamond used all outer electron in bonding.
solubility of diamond
insoluble in both water and organic solvents
hardness of diamond
very hard because of the strong covalent bonds keeps the carbon atoms in fixed position when force is applied.
uses of diamond
tips of drilling or cutting tools
in the structure of graphite, each carbon atom forms covalent bonds with how many other carbon atoms
3
what arrangement/shape does the bonding between atoms results in graphite
hexagonal arrangement/shape
the many layers of graphite are held together by what
weak intermolecular forces
melting and boiling point of graphite
high melting and boiling points
explanation: large amount of energy is needed to break the strong covalent bonds
electrical conductivity of graphite
can conduct electricity
explanation: there are free-moving (mobile) electrons to conduct electricity
solubility of graphite
insoluble in water and organic solvents
hardness of graphite
soft and slippery
explanation: the layers of carbon atoms are able to slide over one another when a force is applied.
uses of graphite
in pencil lead
as a solid lubricant to reduce friction in machinery
in brushes for electric motors and as electrodes
state the type of structure silicon belongs to
giant covalent structure
state the properties of silicon
- melting and boiling point
- electrical conductivity
- hard or soft solid
- solubility in water and organic solvents
- high melting and boiling point
- poor conductor of electricity
- hard solid
- insoluble in water and organic solvents
state the type of structure silicon belongs to
giant covalent structure
state the properties of silicon
- melting and boiling point
- electrical conductivity
- hard or soft solid
- solubility in water and organic solvents
- high melting and boiling points
- non-conductor of electricity
- hard solid
- insoluble in water and organic solvents
metal atoms in the structure loses their valence electron and form what?
positive ions
the valence electrons are __________ , giving rise to ____________.
free-moving, ‘sea’ if delocalised valence electrons
what does the attraction between the positive metal ions and the mobile electrons result in?
metallic bonding
definition of metallic bonding
strong electrostatic attraction between the metal ions and the delocalised valence electrons
melting and boiling point of metals
high melting and boiling point
exception: mercury is a liquid at room temperature
explanation: large amount of heat energy is needed to break the strong metallic bonds
electrical conductivity of metals
metals can conduct electricity in all states
explanation: there are free-moving (mobile) electrons present to conduct electricity.
solubility of metals
insoluble in water and organic solvents
note** some metals react with water to form compounds
lattice definition
it refers to a regular three-dimensional, orderly arrangement of particles
