Main Group Chemistry

Question 1

what is group 1 called

Answer 1

Alkaline metals

Question 2

what is group 2 called

Answer 2

alkaline earths

Question 3

what happens down group 1 +why

Answer 3

reactivity increases as outer electron becomes easier to loose

Question 4

define ionisation energy

Answer 4

energy required to remove the most loosely-bound electron

Question 5

what structure do halides have

Answer 5

6,6 rock salt structure

Question 6

describe the enthalpies of formation of group 1 halides

Answer 6

large+ negative

Question 7

what does the reaction between a hydrogen and a group 1 element produce

Answer 7

ionic (saline) hydrides

Question 8

what is sodium hydrogen carbonate used in

Answer 8

-fire extinguishers
-a raising agent

Question 9

how is sodium carbonate prepared

Answer 9

by bubbling Co2 through a saturated solution of sodium carbonate

Question 10

how do group 1 elements react with water

Answer 10

violently

Question 11

what are metal-ammonia solutions used as

Answer 11

reducing agents

Question 12

why do chelating ligands form more

Question 13

what’s a complex ion

Answer 13

-ligand+ metal cation
-an ion that contains 1 or more ligands attached to a central metal cation via a dative covalent bond

Question 14

how do you find out the coordination number

Answer 14

it’s the same number as the number of ligands attached to the metal cation

Question 15

what are the 2 types of valence transition metal ions can have

Answer 15

-primary
-secondary

Question 16

how do you find primary valence

Answer 16

same as oxidation state of metal cation

Question 17

how do you find secondary valence

Answer 17

same as coordination number

Question 18

if the coordination number is 6, what is the shape of the metal coordination complex

Answer 18

octahedral

Question 19

if the coordination number is 4, what shapes can the metal coordination complex be

Answer 19

-tetrahedral
-square planar

Question 20

what is the general trend for the charge on the metal cation and coordination number

Answer 20

as charge increase, coordination number increases(as it binds to more ligands)

Question 21

define a unidentate/monodentate ligand

Answer 21

the ligand only makes one interaction with the metal ion

Question 22

list some monodentate ligands

Answer 22

H20
NH3
Cl-
CN-
SCN-

Question 23

define a bidentate ligand

Answer 23

forms 2 interactions per molecule

Question 24

list some examples of bidentate ligands

Answer 24

-ethylenediamine(En)
-COOCOO

Question 25

how are electrides formed

Answer 25

alkalia metals +crown ethers

Question 26

define enthalpy of hydration

Answer 26

release of energy as interactions form between the metal ion+water molecules

Question 27

in terms of enthalpy of hydration when is the salt water-soluble

Answer 27

if the hydration enthalpy of a salt is equal to or greater than the lattice enthalpy

Question 28

are most group 1 salts soluble or insoluble

Answer 28

water-soluble

Question 29

what is group 15 called

Answer 29

the pnictogens

Question 30

what is nitrogens elemental form

Answer 30

N2, possessing a very strong NtriplebondN

Question 31

describe nitrogen

Answer 31

-very electronegative -very unreactive

Question 32

why is N2 much more electronegative than their group15 elements

Answer 32

as its very small

Question 33

how are nitrides of metals made

Answer 33

-metal elements+nitrogen -thermal decomposition of an amide complex

Question 34

what's NH3 boiling temp

Answer 34

-33degrees celcius

Question 35

why is NH3 boiling temp much higher than other hydrides in group15

Answer 35

due to extensive hydrogen bonding

Question 36

how can you calculate the number of 'extra' electrons that will go into making lone pairs

Answer 36

E=A-X A, number of valence electrons on neutral central atom X, Number of bonds central atom makes to other things

Question 37

what's the structure of NH3

Answer 37

trigonal pyramid

Question 38

what's a Lewis base

Answer 38

donates a lone pair

Question 39

what's a Lewis acid

Answer 39

accepts a lone pair

Question 40

is ammonia a Lewis base or acid

Answer 40

Lewis base

Question 41

what form of nitrogen forms salts

Answer 41

NH4+, ammonium

Question 42

what's an azide

Answer 42

N3-

Question 43

what shape is N3-

Answer 43

linear

Question 44

describe the structure of N3-

Answer 44

-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

Question 45

why are azide salts often unstable

Answer 45

due to their tendency to decompose explosively with release of N2 gas

Question 46

what's the formula of nitrous oxide

Answer 46

N2O

Question 47

what's the formula of nitric oxide

Answer 47

NO

Question 48

what is NO oxidation state

Answer 48

+2

Question 49

what are sources of NO

Answer 49

-lightening strikes -internal combustion engines

Question 50

what formula does nitrite have

Answer 50

NO2-

Question 51

what shape is the nitrite ion

Answer 51

symmetric +bent