bonding Flashcards
what do bonds between atoms always involve
outer electrons
why are noble gases very unreactive
because their outer main levels are full so have no need to react
why do atoms bond together
they will share or transfer electrons to gain a more stable electron configuration like noble gases - be jelly!!!
what is ionic bonding between
between oppositely charged ions and they will transfer their electrons from metal to non metal shells to obtain the full main outer level
what will happen as a result of ionic bonding
the metal will become positively charged - looses an electron - cation
the non- metal will become negatively charged gains the electrons from the metal - an anion
what force joins ionic compounds together
electrostatic forces of attraction
what are some properties of ionic compounds
- solids at room temp
- brittle - this is because of the oppositely charged ions and a blow in the wrong direction could cause the ions to come into contact that have like charged
- only conduct electricity when molten
why are ionic compounds solids at room temp
because of their macromolecular ionic lattice and the large electrostatic forces of attraction between the ions the amount of energy required to overcome these forces is so large so it will remain solid until large amount of energy is applied.
why can ionic compounds only conduct elec when molten
because when in their giant ionic lattice delocalised electrons are not free to move throughout the structure but when it becomes molten or aqueous the soltion provide a place for delocalised electrons to carry charge
what is a covalent bond
bonding between a shared pair of electrons in a non-metal
what is the force of attraction between the nucleus and the electrons called
electrostatic
what are properties composed of molecules
low bpt and mpt - this is because strong covalent bonds are only between the atoms WITHIN MOLECULES
- poor conductors of elec - because the molecules are overall neutral and there are no delocalised electrons to carry charge throughout no structure!
- even if the molecules dissolve into an aqueous solution they will not comduct elec because the molecules will remain molecules
what is co-oordinate bonding
in most covalent bonding the shared pair of electrons will come from both atoms but in coordinate bonding it comes only from one atom
what is a lone pair in coordinate bonding
the atom that is donating a pair of electrons to an electron deficient atom will donate a LONE PAIR to complete the outer shell
will coordinate bonding affect the shape of an molecule
no, though the electrons are only gifted from one atom the shape will be unaffected
where will the arrow in coordinate bonding go from to?
from the lone pair to where it is going
what is the only difference between coordinately bonded covalent bonds and covalent bonds
coordinate bonds are charged whereas the covalent bonds are not
what is metallic bonding
a lattice of positive ions existing in a sea of outer electrons - these outer electrons are delocalised which means they are not tied to a particular atom and so area ble to carry charge easily throughout the structure
what does the number of delocalised electrons in the sea of electrons depend upon
how many electrons have been lost by each metal atom
what are properties of metals
- good conductors of heat and electricity
- malleable - can be beaten into shape
ductile - can be pulled into thin wires
metals are ductile nad malleable because after small distortion ecah metal ion is still in the same environment so the new shape will be retained
high mpt - because they have a giant structures and there is a strong attraction between the metal ions and the delocalised sea of electrons which will make the atoms difficult to separate
define electronegativity
the power of an atom to attract the electron density towards itself within a covalent bond
define polarity
the equal sharing of electrons that are bonded together covalently
which factors will affect electronegativity
- nuclear charge
- the distance between the nucleus and the outer shell
shielding of the nuclear charge by electrons in the inner shell.
what is the trend in electroneg
increases across a period and up a group so the most electronegative element is fluorine 4.0 woohoo
what can a difference in electronegativity cause
a dipole
what is a dipole - may you ask
a difference in charge between two atoms caused by a shift in electron density
are electrons static
noo - electrons are constantly moving in their electron clou thi is how you achieve van der waals and induced dipoles
what does a molecule having a permanent or induced dipole depend upon
its shape and polarity
what is a symmetric molecule???
all bonds are identical and no lone pairs. will not be polar even if individual bonds are polar. the individual dipoles can cancel out… the negatives will all cancel and positives can cancel it is not nessacerialy in equilibrium Cl4 see google for more you poor sod
who came up with the electroneg scale
pauling
