Main Group Chemistry Flashcards
what is group 1 called
Alkaline metals
what is group 2 called
alkaline earths
what happens down group 1 +why
reactivity increases as outer electron becomes easier to loose
define ionisation energy
energy required to remove the most loosely-bound electron
what structure do halides have
6,6 rock salt structure
describe the enthalpies of formation of group 1 halides
large+ negative
what does the reaction between a hydrogen and a group 1 element produce
ionic (saline) hydrides
what is sodium hydrogen carbonate used in
-fire extinguishers
-a raising agent
how is sodium carbonate prepared
by bubbling Co2 through a saturated solution of sodium carbonate
how do group 1 elements react with water
violently
what are metal-ammonia solutions used as
reducing agents
why do chelating ligands form more
what’s a complex ion
-ligand+ metal cation
-an ion that contains 1 or more ligands attached to a central metal cation via a dative covalent bond
how do you find out the coordination number
it’s the same number as the number of ligands attached to the metal cation
what are the 2 types of valence transition metal ions can have
-primary
-secondary
how do you find primary valence
same as oxidation state of metal cation
how do you find secondary valence
same as coordination number
if the coordination number is 6, what is the shape of the metal coordination complex
octahedral
if the coordination number is 4, what shapes can the metal coordination complex be
-tetrahedral
-square planar
what is the general trend for the charge on the metal cation and coordination number
as charge increase, coordination number increases(as it binds to more ligands)
define a unidentate/monodentate ligand
the ligand only makes one interaction with the metal ion
list some monodentate ligands
H20
NH3
Cl-
CN-
SCN-
define a bidentate ligand
forms 2 interactions per molecule
list some examples of bidentate ligands
-ethylenediamine(En)
-COOCOO
how are electrides formed
alkalia metals +crown ethers
define enthalpy of hydration
release of energy as interactions form between the metal ion+water molecules
in terms of enthalpy of hydration when is the salt water-soluble
if the hydration enthalpy of a salt is equal to or greater than the lattice enthalpy
are most group 1 salts soluble or insoluble
water-soluble
what is group 15 called
the pnictogens
what is nitrogens elemental form
N2, possessing a very strong NtriplebondN
describe nitrogen
-very electronegative
-very unreactive
why is N2 much more electronegative than their group15 elements
as its very small
how are nitrides of metals made
-metal elements+nitrogen
-thermal decomposition of an amide complex
what’s NH3 boiling temp
-33degrees celcius
why is NH3 boiling temp much higher than other hydrides in group15
due to extensive hydrogen bonding
how can you calculate the number of ‘extra’ electrons that will go into making lone pairs
E=A-X
A, number of valence electrons on neutral central atom
X, Number of bonds central atom makes to other things
what’s the structure of NH3
trigonal pyramid
what’s a Lewis base
donates a lone pair
what’s a Lewis acid
accepts a lone pair
is ammonia a Lewis base or acid
Lewis base
what form of nitrogen forms salts
NH4+, ammonium
what’s an azide
N3-
what shape is N3-
linear
describe the structure of N3-
-central N atom has 5 valence electrons :
-it makes 2 double bonds to the 2 N beside
-it has a positive charge, so an e- is taken off
why are azide salts often unstable
due to their tendency to decompose explosively with release of N2 gas
what’s the formula of nitrous oxide
N2O
what’s the formula of nitric oxide
NO
what is NO oxidation state
+2
what are sources of NO
-lightening strikes
-internal combustion engines
what formula does nitrite have
NO2-
what shape is the nitrite ion
symmetric +bent
