bonding Flashcards
ionic compounds contain..
a metal and non metal
what happens when ionic compounds form
electron transfer
what us a single covalent bond
a shared pair of electrons
what does the number of unpaired electrons indicate?
the number of covalent bonds that can be made
how many covalent bonds can carbon make
4
what is an ion?
a charged particle
what are cations?
positive ions
what are anions?
negative ions
what is an ionic bond?
the elctrostatic attraction between oppositely charged ions
what do elements lose/gain electrons to achieve?
nobel gas configuration
what is different about transition metals?
do not always achieve nobel gas configuration
what is an ionic lattice?
regular, repeated 3D framework of ions
what is each:
1) Na+ ion sureounded by in NaCl
2) Cl- ion sureounded by in NaCl
1) 6 Cl- ions
2) 6 Na+ ions
what tyoe of crystal structure is NaCl?
cubic
what is decrepitation?
cracking sounds made when an ionic crystalline structure breaks up upon heating
why does ionic solids have high melting points?
strong electrostatic attractions between oppositely charged ions require alot of energy to break
what increases the strength of ionic bonds?
smaller ions and higher charge
why are positive ions smaller than their atoms
losing an electron from an outer shell inscreases the effective nuclear charge pulling electrons closer to the nucleus
why are negative ions larger than their atoms?
effective nuclear charge decreases and increases electron repulsion
wht are ionic compounds usually soluble in water?
water is a polar solvent
why are some ionic compounds not soluble in water
the electrostatic attraction is so strong, water cannot break the lattice apart
why can ionic compounds conduct electrocity when molten or dissolved?
charges are free to move and transport a current
how is a single covalent bond represented
a line
how is a double covalent bond represented
a double line
what is a lone pair
a pair of electrons not involved in bonding
whoch orbitals are used if bonding results in more than 8 calence electrons?
d orbitals
what is another name for a dative covalent bond
coordinate bond
what is a dative covalent bond?
a lone pair is donated into an empty orbital on another atom
what is different about a dative covalent bond?
both electrons come from one atom
how do you represent a dative covalent bond?
an arrow
what is different about the properties of a dative covalent bond and a standard covalent bond?
nothing
define metallic bonding
electrostatic forces between delocalised electrons and positive metal ions in a lattice
why can metals conduct electricity?
delocalised electrons can transport a current
why can metals conduct heat?
delocalised electrons can transfer energy
why are metals malleable/ductile?
laters of metal ions can slide over eachother without distrupting the bonding
why do metals have high boiling points?
requires a lot of energy to break strong electrostatic atteaction between delocalised electrons and positive metal ions
why do transition metals have higher boiling points?
large number of d subshell, electrons delocalise forming stronger bonds
what is another name for a giant covalent structure?
macromolecular
what are crystal structures of simple covalent compounds called?
molecular covalent crystals
give an example of a molecular covalent crystal
ice
name three properties of molecular covalent crystals:
low melting point
brittle
do not conduct electricity
what is an allotrope?
different forms of the same element in the same physicao state
give two allotropes of carbon
diamond
graphite (graphene)
give three properties of diamond
hard
high melting point
does not conduct electricity
give three properties of graphite
lubricant
high melting point
does conduct electricity
what is sublimination?
change of state from solid to gas
why do lone pairs cause more repulsion?
held closer to the nucleus
2 bonding pairs
0 lone pairs:
name
angle
linear
180•
3 bonding pairs
0 lone pairs:
name
angle
trigonal planar
120•
4 bonding pairs
0 lone pairs:
name
angle
tetrahederal
109.5•
3 bonding pairs
1 lone pair:
name
angle
pyramidal
107•
2 bonding pairs
2 lone pairs:
name
angle
bent
104.5•
5 bonding pairs
0 lone pairs:
name
angles
trigonal bypyramid
90• and 120•
3 bonding pairs
2 lone pairs:
name
angle
T shaped
86•
2 bonding pairs
3 lone pairs:
name
linear
6 bonding pairs
0 lone pairs:
name
angle
octahederal
90•
4 bonding pairs
2 lone pairs:
name
angle
square planar
90•
4 bonding pairs
1 lone pair:
name
angles
sawhorse
86• and 117•
what is electronegativity?
the power of an atom to attract electron density towards itself
wht is the most electronegative element?
fluorine
what does electronegativity depend on?
atomic radius- smaller=stronger attraction
nuclear charge- more protons=stronger attraction
shielding- more e-=more shielding=less attraction
what is the trend in electronegativity?
increases across a period and up a group
/^
what dies a delta +ve charge represent?
electron efficient
what does a delta -ve charge represent?
electron rich
why is BF3 non-polar
it is symmetrical
what is another word for polar?
permenant dipole moment
what is an intermolecular force?
a force between molecules
what is an intramolecular force?
a force within molecules
name theee types if intermolecular force
Van dee Waal
dipole-dipole
Hydrogen bond
how do VDW forces occur?
random movement of electrons causes a temporary dipole which induces a dipole in a neighbouring atom, the resulting opposite delta charges attract
what are teo other names for VDW forces?
induced dipole-dipole
london forces
what happens to VDW attraction as atomic radius increases
gets stronger
what is a permenant dipole-dipole force?
interaction between teo permenant dipoles due to the attraction of opposite delta charges
which theee bonds can form hydrogen bonds?
N-H
O-H
F-H
which intermolecular force is the strongest?
hydrogen bonds
why is ice less dense than water?
hudrogen bonds form an open crystalline structure
what sort of molecules dissolve in polar solvents?
polar molecules
what sort if molecules dissolve in non-polar solvents?
non-polar molecules
