Module 2.2

Question 1

What is an orbital

Answer 1

a region of space where one might find up to two electrons with opposite spins

Question 2

what is ionic bonding

Answer 2

the electrostatic attraction between position and negative ions

Question 3

what is covalent bonding

Answer 3

the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 4

what is relative atomic mass

Answer 4

the weighted mean mass of an atom of an element compared with 1/12 of the mass of carbon-12

Question 5

what is relative isotopic mass

Answer 5

the mean mass of an atom of an isotope compared with 1/12 of the mass of carbon-12

Question 6

what is empirical formula

Answer 6

simplest whole number ratio of atoms in a substance

Question 7

how do you calculate number of electrons in a shell

Answer 7

2n^2

Question 8

how do electrons enter shells

Answer 8

at the lowest energy shell available

Question 9

whats the shape and occurrence of s orbitals

Answer 9

spherical shape, one in every principal level

Question 10

whats the shape and occurrence of p orbital

Answer 10

dumbbell shape, 3 in levels 2 upwards

Question 11

whats the shape and occurrence of d orbital

Answer 11

various shapes, 5 in levels 3 upwards

Question 12

whats the shape and occurrence of f orbital

Answer 12

various shapes, 7 in levels 4 upwards

Question 13

what energy level is lower, 4s or 3d

Answer 13

4s

Question 14

what two elements have different electronic configuration and how

Answer 14

chromium - fills 3d singularly then one in 4s
copper - fills 3d in pairs and one in 4s

Question 15

how do you work out the electronic configuration of ions

Answer 15

take from the highest occupied orbital (4s before 3d)

Question 16

what is a giant ionic lattice

Answer 16

oppositely charged ions held in a regular repeating 3D lattice by electrostatic attraction

Question 17

properties of ionic compounds
solubility?
conduction?

Answer 17

very brittle, insoluable in non-polar solvents (polar solvents stabilise the separated ions because the delta+ atoms attract the the negative ions and vice versa), doesnt conduct as a solid as the ions are in a fixed position in the lattice, but does molten and the ions are free to move as the lattice structure is broken

Question 18

what are the properties of simple covalent molecules
conduction?
solubility?

Answer 18

never conduct (no free ions or delocalised electrons), more soluable in organic solvents rather than water, low boiling point as intermolecular forces are always weak (get strong-ER as molecules get a larger surface area)

Question 19

what is dative or (coordinate) covalent bonding

Answer 19

a covalent bond where both of the electrons being shared come from one of the atoms

Question 20

what happens to the main atom in dative bonding

Answer 20

it becomes slightly positive as more of its negative electrons are shared

Question 21

what atoms can expand their octet

Answer 21

non metals in groups 5-7 from period 3 and onwards

Question 22

how many covalent bonds can group 5 elements form

Answer 22

3 or 5

Question 23

how many covalent bonds can group 6 elements form

Answer 23

2,4 or 6

Question 24

how many covalent bonds can group 7 elements form

Answer 24

1,3,5 or 7

Question 25

what is PFv5 called

Answer 25

phosphorus pentaflouride

Question 26

what is SFv6 called

Answer 26

sulphur hexafluoride

Question 27

what are the general properties of giant covalent structures/networks/macromolecules melting point? conduction?

Answer 27

very high melting point due to many strong covalent bonds, don’t conduct bar graphite and graphene (1 spare electron), usually hard because of rigid tetrahedral structure (diamond and silica) but graphite is soft

Question 28

name the main giant covalent structures

Answer 28

diamond, graphite, graphene silica (SiOv2)

Question 29

what is electronegativity

Answer 29

the ability of an atom to attract the bonding pair of electrons in a covalent bond

Question 30

how is electronegativity measured

Answer 30

pauling scale increased up and right

Question 31

what’s the criteria to be a polar molecule

Answer 31

polar bond and unsymmetrical molecule

Question 32

what can we use to measure the strength of a covalent bond

Answer 32

average bond enthalpies

Question 33

when do london forces occur

Answer 33

between all atoms/molecules

Question 34

how do london forces happen

Answer 34

when electrons (always in constant motion) are momentarily more on one side of a molecule creating a temporary/instantaneous dipole which causes an induced dipole in the other molecule/atom

Question 35

when do permanent dipole-dipole interactions happen

Answer 35

between two polar molecules

Question 36

what does hydrogen bonding happen between

Answer 36

a lone pair on a F O or N atom (that’s bonded with a hydrogen) and an H atom (that’s bonded with F O or N)

Question 37

what happens to boiling point when hydrogen bonds are present

Answer 37

higher than expected because the forces are strong and takes lots of energy to overcome

Question 38

describe the structure of ice

Answer 38

each molecule hydrogen bonded to 4 others in tetrahedral structure - open lattice structure - volume is larger than liquid so less dense

Question 39

when is waters maximum density and why

Answer 39

4°C because when ice melts the structure collapses slightly and molecules come closer - then move a little further apart as the get more energy when heated

Question 40

how many lone pairs do O and N have when bonded with hydrogen

Answer 40

2

Question 41

how many lone pairs does F have when bonded with hydrogen

Answer 41

3

Question 42

why is hydrogen bonding so strong

Answer 42

because the interaction is extremely polar (only with the most electronegative elements) AND the small sizes of H F N and O are concentrated in a small volume so a high charge density

Question 43

what is a permanent dipole

Answer 43

the charge different between the two bonded atoms in a polar bond

Question 44

why are symmetrical molecules never polar molecules

Answer 44

because the dipoles act in different directions in an equal distribution so they cancel eachother out

Question 45

how does a greater electronegativity difference impact polarity

Answer 45

greater difference = greater polarity

Question 46

what factors affect electronegativity

Answer 46

nuclear charge, distance from nucleus and electron shielding

Question 47

do you remove from 4s or 3d first for ions??

Answer 47

4s