1.Foundations in chemistry, Periodic table and enegy Flashcards
topic 1 and 2
1
Q
Ionic bond definition
A
the electrostatic attraction between opp. charged ions
2
Q
covalent bond definition
A
the strong electrostatic attraction between a SHARED PAIR of electrons and the NUCLEI of the bonded atoms
3
Q
linear- bond angle /electron pairs/ example
A
180/ 2 bonding pairs of electrons / Co2
4
Q
trigonal planar- bond angle /electron pairs/ example
A
120/ 3 bonding pairs of electrons/ Bcl3
5
Q
tetrahedral- bond angle /electron pairs/ example
A
109.5 / 4 bonding pairs of electrons /CH4
6
Q
pyramidal- bond angle /electron pairs/ example
A
107/ 3 bonding + 1 lone pair/ NH3
7
Q
non-linear- bond angle /electron pairs/ example
A
104.5 / 2 bonding = 2 lone / H2O
8
Q
octahedral- bond angle /electron pairs/ example
A
90 / 6 bonding pairs of electrons / SF6
9
Q
electronegativity definition
A
the ability of an atom to attract the bonding electrons in a covalent bond
10
Q
first ionisation energy definition
A
the energy required to remove one electron from every atom in one mole of GASEOUS ATOM
11
Q
metallic bond definition
A
a strong electrostatic attraction between CATIONS and delocalised electrons
12
Q
4 types of structure and boning
A
giant ionic
giant covalent
giant metallic
simple molecular/ covalent
13
Q
describe the structure and bonding of a giant ionic lattice
A
-giant structure
-ionic bonding
-strong electrostatic forces of attraction
-in a GIANT IONIC LATTICE where forces act in ALL directions
14
Q
3 properties of ionic compounds
A
-high melting/ boiling point
-conducts electricity when DISOLVED in water/ moltten
-poor conductors when SOLID
15
Q
why do giant ionic compounds have a high melting point?
A
- strong elaectrostatic forces oif attraction IN ALL DIRECTIONS
-between opp. charged ions
-STRONG ionic bonds need lots of energy to break
16
Q
why do giant ionic compounds have good electrical conductivity when molten/ dissolved in water?
A
-when molten/ disolved in water
-ions can m,ove freeley
-ions are mobile charge carriers
17
Q
why do giant ionic compounds have bad electrical conductivity when solid?
A
-when solid
-ions are fixed
-and cant move
- are not mobile charge carriers
18
Q
another word for dative covalent bonding?
A
coordinate bonding
19
Q
why are electrons spread out in pairs?
A
-electron pairs repel ( as both are -ve)
-forced maximum distance apart
-lone pairs repel more than bonded pairs of electrons
(pairs of electrons repel other pairs of electrons)
20
Q
pattern in electronegativity on the periodic table? and explination?
A
-increases as you move across a period (L-R)
more protons in the nucleus from (L-R)
increase in nuclear attraction between protons in the nucleus and electrons in the outer shells
-increases as you move up a grp
as you move up a grp atom size decreases
it is easier to get an electron closer to the nucleus
(increases in a diagonal across periodic table from FR to F)
21
Q
what does a delta (δ) symbol show in a permenant dipole?
A
-a slight charge
δ+ is least electronegative
δ- is most electronegative
22
Q
what is the most electrongative element?
A
flourine
23
Q
what is a polar molecule?
A
- have bonds with a permanent dipole
-the molecular shape must not cause dipoles to cancel each-other out
24
Q
what are the anomalous properties of water? and explain?
A
- Ice is less dense then water
coz ice has an OPEN lattice structure
Hydrogen bonds in the lattice hold the water molecuels
apart
-water has a relativley high boiling and melting point
coz it has hyfrogen bonds in addition to london forces
so more energy is needed to overcome the additional hydrogen bonds
25
26
what 3 elements can a hydrogen bond be formed with?
F
O
N
27
what delta charge is hydrogen
δ+
28
what delta charge does F/O/N have?
δ-
29
why metals have high melting point
-giant mettalic lattice
-strong metalic bonding
-lots of energy to break
30
why metals are good cobductors of electricity
have mobile delocalised electrons
which are mobile charge carriers
31
why metals dont disolve in water?
metalic bonds are too strong to be broken down by water
32
graphite structure
giant covalent lattice
layers of hexogons(trigonal planer angle 120)
each carbon atom has 3 strong covalent bonds
1 delocalised electron
33
graphite properties
good conducter of electricity
high melting point
desont disolve in water
34
why is graphite a good conductor of electricity?
each carbon atom has a delocalised electron
which can move through the structure
acting as mobile charge carriers
35
why graphit has a high melting point
giant covalent lattice
3 strong covalent bonds per atom
lots of energy to break
36
why dosent it disolve in wtaer?
not polar
has strong covalent bonds whicha re too strong to be broken down by water
37
structure of diamond and silicone
- giant covalent lattices
-each c atom has 4 strong covalent bonds
(no layers)
(no delocalised electrons)
38
diamond and silicone properties?
high melting point
39
why do diamond and silicone have a high melting point?
giant covalent lattice
4 strong covalent bonds per c atom
reuires lots of energy to break
40
why are silicone and graphite poor conductors of electricity
no delocalised electrons
which act as mobile charge carriers
41
nitric acid formula
HNO3
42
difference in melting point in the same period exsplained?
e.g P4 and cl2
P4 has a higher melting poit because it has stronger london forces (coz more e-)
more energy needed to break the intermolecular forces
43
why is a mollecule is polar
molecule isnt symetrical
dipoles dont cancel out
44
giant ionic lattice defenition
repeating pattern
of oppositley charged ions
45
orbital defenition
a region around the nucleus that can hold 2 el;ectrons (with opposite spin)
46
order of filling
1s/ 2s/2p/3s/3p/ (4s) /3d/4p
47
relative atomic mass (RAM) definition
weighted mean mass of an atom of an element to 1/12th of an atom of carbon- 12
48
relative isotopic mass (RIM)
the mass of an isotope relative to 1/12th of the mass of an atom of carbon-12
49
RAM equation
(mass x abundance) + (mass x abundance)/100
50
the 3 general reactions of acids
1) Acid + Alkali/base -> salt + water
2) Acid + Carbonate -> salt + carbon dioxide + water
3) acid + metal -> salt+ hydrogen
51
nutralisation reaction
H+ +OH- -> H2O
52
layers in an electron shell from biggest to smallest
shell-> subshell-> orbital
53
how many electrons in an orbital?
2
54
s subshell orbitals and electtrons?
s 1 orbital (2e-)
55
p subssell orbitals and electrons
3 orbitals n(6e-)
56
d subshell orbitals and electrons?
5 orbitals (10e-)
57
f orbitals
7 orbitals (14e-)
58
p orbital shape
dumbell
58
s orbital shape?
sphere
59
isotope definition
atoms with the same number of protons but a different number of nutrons and different masses.
60
what is the relative mass of an electron
1/1836
61
what are charges and masses of subatomic particles relative to
the proton
62
short hand electron arangement
63
isotopes of hydrogen
64
acid deffenition
H+ proton donor that releases H+ ions in aqueous solution
65
what 4 acids do u need to know?
1) hydrochloric acid -> HCL
2)Nitric Acid -> HNO3
3)H2SO4 -> Sulphuric Acid
4)ethanoic acid -> CH3COOH
66
alkali definition
soluble basses that release OH- ions in aqueous soloution
67
4 alkalis to know
1) sodium hydroxide ->NAOH
2)potassium hydroxide
->KOH
3)amonia->NH3
4)amonia in water (amonium hydroxide)->NH4OH
68
what is a polyatomic ion
an ion contyaining 2 or more eleements
69
what is Avogadro's constant
6.02×10²³ mol⁻¹.
70
STRONG AND WEAK ACIDS DISSOCIATIONS
71
moles formula with Avogadro's constant ?
N number of atoms
--------------------- = --------------------------------------
n x Av moles x Avogadro's constant
72
moles calculation and steps for solids?
steps
1)calculate moles
2)the ratio
3)mass
MASS
--------------------------
MOLES I Mr
I
73
what are gasses measured in?
volume
74
what are the calculations for moles in gasses? AND THE STEPS
volume (cm3) volume (dm3)
------------------------------------------- or --------------------------------
moles I 24, 000(cm3) moles I 24(dm3)
I I
steps
1)calculate moles
2)the ratio
3)voleme
75
what is mole of any gas?
24,000 cm3 or 24 dm 3
76
moles calculations for solutions (aq)?
moles
------------------------
conc. I volume
77
what is the unit for concentration
mol/dm3
78
titrations
79
what is the empirical formulae?
the simplest whole number ratio of atoms in a compound
80
steps for emirical formulae
steps
1)mass
2) mass/Ar
3)divide all ratios by the lowest ratio
81
water of crystalisation
82
Ideal gas equation and units
pV = nRT
P= pressure in pascal (Kpa x 1000= Pa)
volume =m3 (dm3-->m3 is ÷ 1000) (cm3 -> m3 is ÷ 1,000,000)
n= moles
R= gass constant in exam aid (8.3-4 J mol-1 K-1)
T= temperature in kalvin (K)
83
formula for Kalvin
C+ 273=K
c= Celsius
84
formula for celcius
k-273= Celsius
k= Kalvin
85
what is ideal gass?
1 mole of any gas - occupies 24dm3 at room temp and pressure
86
what temp. is room temp.?
20 degree c or 293k
87
what is room pressure
101 kpa
88
how to reduce percentage uncertanty in mass
- use balance that weighs to more decimal places
- use a larger mass
89
use of aqueous barium chloride in quantitative analysis test
-test for sulphate
-white precipitate forms
90
-test for sulphate ions and results
use of aqueous barium chloride in quantitative analysis test
-white precipitate forms
91
molecular formula deffenition
the actual number of atoms of each element in a compound
92
Q
what is the oxidation state of an element?
0
93
why increased temp. means increased rate of reaction
-increased temp. means activation energy is reached
-so increased kinnetic energy of reactant particles
-increased frequency of succesfull collisions between reactant particles
94
draw catalyst and boltzmann
and explanation
-catalyst decreases the EA
-by providing an alternative reaction pathway
-so a greater proportion of molecules have energy exceedin EA
-causes an increased rate of reaction
95
draw temperature and boltzmann
and explanationv
-increased temp
-so greater proportion of molecules with energy exceeding the EA
- increased kinnetic energy so more FREQUENT collisions
-therfore increased rate of reaction
96
rules for drawing energy diagram
- draw all the arrows facing up
then go back and draw arrows facing down
97
oxidation in terms of electrons
loss of electrons
98
reduction in terms of electrons
gain of electrons
99
oxidation in terms of oxidation state
increase in oxidation state
e.g (0 to +2)
100
reduction in terms of oxidation state
reduction in oxidation state (0 to -2)
101
a general equation for a typical redox reaction
metal+ acid -> salt+ hydrogen
102
what is calcium hydroxide
lime water
103
hydroxide general equation
oxide(s) + water(l) → hydroxide(aq)
104
what causes an increase in ph (not spec friendly)
more hydroxide ions, OH–, dissociate into a solution cause the pH to increase
105
trend in solubility of group 2
- increase solubility down the grp
-higher ph/ becomes more alkaline
-coz more OH- released
-so there is a higher conc. of oh- ions present.
106
barium oxide and water equation
(BARIUM CAN BE SWAPPED WITH LITERALLY ANY GRP 2 METAL)
BaO(s) + H₂O(l) →Ba(OH)₂ (aq)
107
another name for group 2
alkaline earth metals.
108
what are the uses for group 2 Compounds
- Indigestion treatments
- agriculture
109
what grp 2 compounds are used in agriculture and why
calcium hydroxide Ca(OH)₂
to increase the Ph of the soil and make it more alkali
equation Ca(OH)₂ + H₂SO₄ → CaSO₄ + 2H₂O
110
what grp 2 compounds are used in indigestion treatment
CaCO3 EQUATION: CaCO₃ + 2HCl → CaCl₂ + H2O + CO₂
and
Mg(OH)₂ EQUATION: Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O +
111
why are group 2 metals s block elements
(why is nay element in any block)
the highest energy electron is in an s sub shell
112
what is the trend in reactivity of group 2 and why
-the reactivity of grp 2 increases DOWN a period
-and become more powerful reducing agents
-because the outer shell electron is lost more easily
COZ
-sum of 1st and 2nd ionisation energy decrease down the grp
-nuclear attraction decreases
- coz larger atomic radius means greater electron sheilding
113
what are the 3 redox reactiions of grp 2 that I need to know?
Metal+water -> metal hydroxide + hydrogen
Metal+oxygen -> Mrtal oxide
Metal+acid ->salt + hydrogen
114
general equation for grp 2 and oxygen
2M(s) + O₂(g) → 2MO(s)
115
general equation for grp 2 and water
M(s) + 2H₂O(l) → M(OH)₂ (aq) + H₂
116
general word equation for grp 2 and acids
metal + acid → salt(aq) + hydrogen(g)
117
what shell do all halogens end in
(s2 or p5)
118
what is the grp 7 trend in boiling point
- boiling point increases down the group
-more electrons
-more London forces between molecules
- more energy needed to overcome
119
what is the grp 7 trend in reactivity
- decrease down a grp
- weaker oxidising power
-increased number of electrons
-more shielding
-larger atomic radius
-weaker nuclear attraction
-harder to gain electrons
120
Observations with an organic solvent
121
Observations in aqueous solution
122
what are the 3 displacement reactions I need to know
Cl and Br
Cl and I
Br and I
123
what are the 3 displacement reactions Ionic I need to know
1) Cl₂ (aq) + 2Br-(aq) → 2Cl- (aq) + Br₂ (aq)
2) Cl₂ (aq) + 2I-(aq) → 2Cl- (aq) + I₂ (aq)
3) Br₂ (aq) + 2I-(aq) → 2Br- (aq) + I₂ (aq)
124
what is disproportionation
when the same element is oxidised and reduced
125
what example of a disproportionation do i need to learn
chlorine with COLD aqueous sodium hydroxide
Cl₂(aq)+ 2NaOH(aq) → NaCl(aq)+ NaClO(aq) + H₂O (l)
126
NaClO(aq) household name
bleach
127
bleach chemical formula
NaClO(aq)
128
halides with silver nitrate general ionic equation
Ag+ (aq) + X-(aq) → AgX(s)
129
what precipitates form with silver nitrate chlorine bromine and iodine
AgCl = white
AgBr= cream
AgI+ yellow
130
further testing with amonia results
AgCl = redisolves in dilute amonia
AgBr= redissolves in concentrated amonia soloution
AgI+ does not redisolve
131
Homologous series
a series of organic compounds having the same funtional group but with each sucessive members differing by CH2
132
what are the blocks in the periodic table
s,d,p,f
132
divide a periodic table into its blocks
133
fraw 2 molecules of water together
133
trend in electronegativity
-increases across a grp
(as atomic radius decreases more protons in nucleus as u move from l-R)
decreases as you move down a grp
coz atom size increases so it is harder to get an electron closer to the nucleus
133
what 3 elements form a hydrogen bond
f
o
n
134
anomolous prperties of water
-ice is less dense than water
-open lattice structure
-the H bonds in the lattice hold the water molecules apart
-water has a relativley high boiling point
-coz it has H bonds in addition to london forces
-which require lots of energy to overcome
134
1st and 2nd ionisation energy equation
E(g) --> E+ + e-
E+(g)--> E2+ +e-
134
why does ionisation energy increase evrytime you remove an electron
because increased +ve charge
so greater nuclear attraction by remaining electrons
135
Ionisation energy down a grp
136
Ionisation enegy across a grp`1
137
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