definitions

Question 1

ionisation energy

Answer 1

the energy required to remove an electron from a gaseous atom or ion

Question 2

factors affecting ionisation energy

Answer 2

charge on the nucleus (the more protons preset within the nucleus the more positive it becomes and hence the electrons that are attracted to it)

the distance between the nucleus and the electron (the closer the electron is to the nucleus the stronger the attractive force between them is and therefore the harder it will be to remove it)

shielding or screening

Question 3

effective nuclear charge

Answer 3

Z (number of protons) - sigma (screening constant)

Question 4

screening constant

Answer 4

write out electron configuration
group the electron groups (1s, 2s, 2p, 3s, 3p…)
ignore the outermost electron due to screening
outermost is 0.35 per electron
2s groups = 0.85 each
1s groups = 1.00 each
calculate overall nuclear charge (number of protons)
use formula

Zeff = Z - sigma

Question 5

ionisation energy

Answer 5

increases across a period (no increase in screening)
decreases down a group (electrons in the outermost shell get further from the nucleus going down a group)

Question 6

electron affinity

Answer 6

the amount of energy absorbed or released when an electron is added to a neutral atom in the gas phase

positively charged electron affinity = energy released when the electron is added to the atom

negatively charged electron affinity = energy is required t add the electron to the atom

Question 7

atomic radius

Answer 7

half the distance between two nuclei in a molecule of two identical atoms

decreases going across a period (increasing nuclear rage decrease in screening)

increases going down a group (increasing number of shells)

Question 8

ionic bond

Answer 8

one or more electrons are donated from one atom to another

Question 9

covalent bond

Answer 9

valence electrons are shared

Question 10

electronegativity

Answer 10

a measure of how well an atom is able to pull electrons towards the nucleus

difference >2 = ionic
difference <0.4 = covalent
0.4 <difference <0.2 = polar covalent

increases going across a period
decreases going down a group (due to increasing atomic radius, increasing the distance from the valence electrons to the nucleus)

Question 11

polar covalent

Answer 11

electrons are shared (covalent) but shared unequally (polar)

Question 12

intra vs inter

Answer 12

inter = between (weaker)
intra = within (stronger)

Question 13

dipole

Answer 13

a partial charge on an atom

ion-dipole bonds are much stronger than dipole-dipole bonds as the charge of an ion is much stringer than any dipole

Question 14

dipole-dipole forces

Answer 14

when two dipolar molecules interact with each other and the partially positive side of one dipolar molecule bonds with the partially negative side of the other dipolar molecule

Question 15

London dispersion forces

Answer 15

the weakest intermolecular force

temporary electron arrangement that triggers a temporary dipole causes temporary dipoles in neighbouring molecules

factors that affect London dispersion forces (shape of molecule, number of electrons (more electrons lead to grater dispersion forces)

Question 16

hydrogen bonding

Answer 16

Hydrogen covalently bonds to a highly electronegative atom (N O F)

strongest dipole-dipole force

Question 17

bond pair and lone pair

Answer 17

a pair of electrons that is share between the two atoms (bond pair)

electrons not involved in bonding (Lone pair)

Question 18

valency

Answer 18

the ability of an atom or a group of chemically bonded atoms to form chemical bonds with other atoms or groups of atoms

Question 19

valency according to groups

Answer 19

group 1 = +1
group 2 = +2
group 3 = +3
group 4 = +/- 4
group 5 = -3
group 6 = -2
group 7 = -1
group 8 = 0

Question 20

the preferred geometry of a molecule

Answer 20

is one that maximises the separation of electron pairs and that bonding and lone pairs will be as far apart as possible

Question 21

shapes (no lone pairs)

Answer 21

linear = 180 (2 groups)
trigonal planer = 120 (3 groups)
Tetrahedral = 109.5 (4 groups)
trigonal bipyramidal = (3x groups = 120, 2x groups = 90)
octahedral = 90 (6 groups)

Question 22

shapes (lone pairs present)

Answer 22

trigonal pyramidal = 107 (3 bond pairs, 1 lone pair)
bent = 104.5 = 2 bond pairs, 2 lone pairs (water)

Question 23

naming inorganic compounds

Answer 23

binary ionic compounds (consist of only two elements, contain a cation + and an anion -)

the cation goes first and then the anion goes last

Question 24

list of cations and anions

Answer 24

Cations (Hydrogen H+, Lithium Li+, Sodium Na+, Potassium K+, Caesium Cs+, Beryllium Be2+, Magnesium Mg2+, Calcium Ca2+, Barium Ba2+, Aluminium Al3+)

Anions (Hydride H-, Fluoride F-, Chloride Cl-, Bromide Br-, Iodide I-, Oxide O2-, Sulphide 2-, Nitride 3-, Phosphide 3-)

Question 25

more than two ions in the series

Answer 25

more than two ions = ate gets prefix per
less than two ions = ite gets prefix hypo

Question 26

broad structure of solids

Answer 26

crystalline (solids whose atoms/ions/molecules are ordered in well-defined arrangements, flat surfaces, highly regular shape and high defined melting point)(made up of repeating units called unit cells which form a lattice point, a lattice point is a point in space occupied by an atom ion or molecule).

amorphous (a large degree of disorder in their structure, broad melting point)

Question 27

cubic unit cells

Answer 27

unit cells that have equal edge lengths and 90 degree angles at their corners

simple cubic (edge length is twice the radius of the atom)
body centred cubic
face centred cubic

Question 28

lattice constant

Answer 28

to find the volume of the cube = (lattice constant)^3

simple cubic - lattice constant = 2r

face centred - 4r/square root of 2

body centred cubic: 4r/square root of 3

Question 29

avogadros number

Answer 29

6.022x10^-23

Question 30

moles =

Answer 30

mass / molecular weight

Question 31

moles to molecules or atoms

Answer 31

multiply moles by avogadros number

Question 32

sigma bond

Answer 32

head on overlap of orbitals
single bond has 1 sigma bond
double bond has 1 sigma bond and 1 pi bond
triple bond has 1 sigma bond and 2 pi bonds

Question 33

pi bond

Answer 33

side on overlap of orbitals

Question 34

bond strengths

Answer 34

the greater the orbital overlap, the stronger the bond and the shorter the bond will be

Question 35

VB theory

Answer 35

describes how atoms form covalent bonds in molecules

Question 36

hybridisation

Answer 36

the mixing of atomic orbitals on an atom to form new hybrid orbitals

Question 37

percentage yield

Answer 37

actual yield/theoretical yield x 100