(11) solid state inorganic

Question 1

define crystalline materials

Answer 1

atoms, ions or molecules are aligned throughout the crystal in fixed orientations. No movement

Question 2

how is a single crystal composed

Answer 2

A single crystal containing regularly repeated 3D lattice

Question 3

define unit cell

Answer 3

smallest unit of volume which has a unique pattern from which a lattice is built

Question 4

define liquid crystals

Answer 4

some degree of order in one or two dimensions but not as regular as a crystalline material

Question 5

define amorphous material

Answer 5

disordered solids - solids that have a similar structure to liquids

Question 6

how do you calculate the volume of a unit cell

Answer 6

volume = a x b x c x sinA x sinB x sinC

Question 7

define coordination number

Answer 7

number of atoms bonded to another particular atom

Question 8

define coordination geometry

Answer 8

arrangement of ligands around a particular atom

Question 9

when coordination number = 2 what Is the name of the shape

Answer 9

linear or bent

Question 10

when coordination number = 3 what Is the name of the shape

Answer 10

trigonal planar , pyramidal, t shaped

Question 11

when coordination number = 4 what Is the name of the shape

Answer 11

tetrahedral, square planar

Question 12

what are the positions of atoms within the cell defined by

Answer 12

fractional coordinates

Question 13

what is the formula to calculate density of the crystalline solids

Answer 13

density = nM/(Vx 10-24 x6.023x-23) g/cm3

Question 14

what is the difference between the bonding in molecular solids and network solids

Answer 14

molecular = van der waal
network = covalent

Question 15

why do molecular solids have low boiling points

Answer 15

van der waal intermolecular forces are the weakest so require a small amount of energy to overcome

Question 16

what type of bonding has NO intermolecular forces of attraction

Answer 16

network solids - just covalent bonding

Question 17

describe the structure within a metallic solid

Answer 17

• valence electrons are delocalised
• free electrons form a sea around metal ions
• ions are fixed, electrons are free

Question 18

why dont atoms have fixed atomic radiuses

Answer 18

the radius of an atom depends on the intermolecular forces between the atoms

Question 19

what is the trend between oxidation state and the atomic radiuses and why

Answer 19

as oxidation state increases, atomic radius decreases BECAUSE as the oxidation state increases, the net positive charge on the nucleus increases. This therefore decreases the EFFECTIVE NUCLEAR CHARGE

Question 20

describe X-ray diffraction

Answer 20

x-ray photons are scattered by electrons surrounding the nucleus

Question 21

describe electron diffraction

Answer 21

electrons are scattered by electrons of the atom usually in gases. Experiments must take place in a vacuum

Question 22

describe neutron diffraction

Answer 22

scattering from the nucleus - which doesn’t depend on atomic number. This is why hydrogen can be considered a ‘heavy; element

Question 23

what does single crystal x-ray/neutron diffraction produce?

Answer 23

It allows the calculation of individual factional coordinates of every atom in the unit cell. This can be used to calculate the fractional coordinates of the whole crystal. This generates the picture.

Question 24

what does Powder x-ray/ Neutron diffraction produce

Answer 24

Micro crystalline powders can be used, but diffraction patterns of complex structures are difficult to determine