Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CH2501 > S-Block > Flashcards

S-Block Flashcards

1
Q

what % of the mass of the atom is the nucleus?

A

> 99.94%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

quantum numbers: n, l, ml, ms

A

n = shell, l = s-0,p-1,d-2… ml = -1,0,1 etc, ms = +/- spin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

atoms in ground state, orbital filling order?

A

Fill: 1s,2s,2p,3s,3p,4s,3d,4p,4d…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

vertical columns?

A

groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

horizontal columns?

A

periods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

4f elements?

A

lanthanoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

5f elements?

A

actinoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

S block groups?

A

Gp1 - alkali metals. Gp2 - alkaline earth metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ionisation energy?

A

energy required to remove one electron, from gas phase to form cation.
endothermic process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

ionisation energy trend?

A

decrease down the group. more protons = higher nuclear charge = stronger pull = so smaller “size” = higher IE energy required for further removal. shielding effect means decrease in energy down group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

electron affinity?

A

the electron gain energy (Eeg), energy change change when one electron is added to one atom in gas phase to form an anion. also known as electron affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

relationship between electron affinity and electron gain?

A

Ea = - Eeg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

trends of Ea

A

exothermic electron uptake forms stable Nobel gas configuration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

electronegativity?

A

dimensionless. ability to attract electrons in a chemical bond using Pauling scale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

electronegativity trend?

A

EN increases across a period and decreases down a group. EN increases with higher oxidation states, this is to do with the charges of ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

electropositivity?

A

ability to donate electrons in a bonding interaction. alkali metals very electropositive (low first ionisation energy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

metalloids?

A

semimetals. B, Si, Ge, As, Sb, Te, Po. metal character, intermediate properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

metals?

A

s - block elements. low ionisation energy and low electronegativity (X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

non metals?

A

high ionisation energy and high electronegativity (X)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

metal characteristics

A

metallic shine. electric and thermal conductors. outer electrons move freely (sea of delocalised electrons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

malleability and ductility

A

malleable - formed without breaking
ductile - drawn into wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

atomic and ionic radii?

A

atomic radii - radius in the metal element, assuming hard sphere
ionic spheres - comparing ionic compounds and ions
depends on elements and charge of the ion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

atomic radii trend?

A

Atomic radii increase towards bottom left of periodic table. Caesium is largest atom. - Atomic radii decrease across the period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Alkali metals?

A

Li, Na, K, Rb, Cs, Fr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

alkali metals properties?

A

silvery white, soft metals, highly reactive, strong reducing agents

26
Q

alkali metals electron configuration

A

[Ng] s1

27
Q

Na+ and K+ uses

A

minerals/electrolytes in human body; blood pressure regulation, action potentials for nerve cells
NaCl for seasoning

28
Q

Lithium salts uses?

A

carbonates, acetates, citrate
treatments for manic-depressive psychoses (bipolar disorder) as a mood stabiliser

29
Q

trends down the Gp1 period?

A

atomic radius increases
ionisation energy decreases
mp and bp decreases
weak metallic bonding between atoms
density increases (but got low density)
enthalpy of sublimation decreases (turn to gas phase)

30
Q

preparation of alkali metals?

A

Li and Na prepared by electrolysis of their molten salts by DOWNS process
electrolysis of molten NaCl at 600ºC and 4-8 eV

31
Q

reaction of Na and Cl?

A

2 NaCl (l)  2 Na (l) + Cl2 (g)

32
Q

Downs Process?

A

> 50%
CaCl2 additives to keep the salt liquid below the NaCl melting
point of 801°C; Ca2+ is more difficult to reduce than Na+, a
carbon anode and an iron cathode are used

33
Q

Na and K reactions?

A

K+ and Na+ stored under oil, as reactive in oxygen
K+ cannot be prepared by electrolysis (too reactive)

Na + KCl –> NaCl + K
at high temp, to drive equilibrium in substitution reaction

34
Q

alkali metals reduction potential?

A

heavier alkali metals are more reducing than the lighter ones

35
Q

Uses of sodium metal?

A

synthesis of tetraethyl leads as a fuel additive for anti knocking properties

4 NaPb + 4 EtCl → PbEt4 + 3 Pb + 4 NaCl

released alot of lead into the atmosphere

36
Q

alkali metals as drying agents?

A

Na, K and Na/K with water can be used to dry chemicals effectively.
Using a metal that will be liquid at the solvents boiling point, can reflux under inert gas and distil away the solvent

37
Q

alkali with oxygen/air reaction?

A

4 Li + O2 → 2 Li2O (oxide, O2-)
2 Na + O2 → Na2O2 (peroxide, O22-, with O-O single bond)
5
K + O2 → KO2 (superoxide, O2
*-, radical anion) this is very unstable

38
Q

super oxides?

A

KO2 is a superoxide. yellow, paramagnetic and shock sensitive

39
Q

Hydrolysis of KO2

A

4 KO2 (s) + 2 H2O (l) → 4 K+
(aq) + 4 OH-
(aq) + 3 O2

HO2 is not stable due to disproportionationation and gives O2

hence needs to be kept in inert gas

40
Q

Reaction of KO2 with CO2

A

4 KO2 + 2 CO2 → 2 K2CO3 + 3 O2; 4 KO2 + 4 CO2 + 2 H2O → 4
KHCO3 + 3 O2.

O2 is released so they can be called oxygen generators in space suits

41
Q

lithium reaction with nitrogen

A

6 Li (s) + N2 (g) = 2 Li3N (s)

has to be stored under argon

forms strong triple bonds

Li+ able to form stable lattice with N3- anions. cannot be done with larger anions, overcoming disassociation energy

N3- is hard and small and this needs to be balanced by also small metals ie 3x Li+1

42
Q

alkali metal reaction with water?

A

react violently (exothermic)

2 M (s) + 2 H2O (l) -> 2 MOH (aq) + H2 (g)

more reactive down the group as Heavier metals quickly melt with the heat of the reaction, this melting causes new metal surface to be exposed and accelerates the reaction

43
Q

Sodium/Potassium alloy

A

Na/K alloy is liquid at and below room temperature. Na/K alloy (40-90 weight % K): large liquid
range (-13°C to +785°C for 77% K; ca. K2Na)
Na/K is sometimes used as a liquid coolant in nuclear facilities (e.g. experimental nuclear
reactors)! The alloy has a good thermal conductivity.

44
Q

Intercalation compounds?

A

alkali metals with graphites, graphites are reduced and M+ cations intercalate and coordinate to 6 membered rings between the graphite layers (expanding to fit)

these are strong reducing agents

45
Q

intercalation compounds properties?

A

gives bronze-
coloured highly reactive intercalation
compound. KC8 is a strong reducing agent. It is
a powder that can be readily handled under dry
inert gas. It is pyrophoric and in air
spontaneously bursts into flames.

46
Q

LI-graphite intercalation compounds?

A

formula: LiC6

negative anode
LiC6 → Li+ + “C6” + e-

positive cathode
CoO2 + Li+ + e- → LiCoO2

used in rechargeable batteries. The small Li+ can migrate; moves in and out of the solid structures (“C” and
CoO2)  a reversible system that can be recharged (the opposite reactions).

an electrolyte, e.g. LiPF6 in an organic (non-protic) solvent such as diethyl carbonate, and separator
diaphragm (permeable for Li+)

47
Q

sodium with water

A

Na + H2O = NaOH + H2

48
Q

electrolysis of aq NaCl?

A

NaCl = NaOH + Cl2 and H2 (chloralkali process)

NaCl is able to be mined or obtained by evaporation of seawater

49
Q

alkali metals with halogens?

A

Alkali metals + halogens = MX salts (colourless and ionic), in an exothermic reaction

50
Q

MX salt preparation

A

alkali metals hydroxide/carbonates + hydrohalic acid (HX) = salt + water (+carbon dioxide)

Li2CO3 (aq) + 2 HBr (aq) → 2 LiBr (aq) + H2O (l) + CO2 (g)

51
Q

solubility of MX halides

A

are water soluble, except LiF cause it is sparingly soluble due to large lattice energy (2x small hard ions) which is not overcome by hydration enthalpy and has the largest lattice energy, which not offset by enthalpy of hydration

52
Q

alkali metal hydrides?

A

Liquid metal + hydrogen gas = Alkali metal hydrides

these are ionic due to EN difference

2 M + H2 → 2 MH

53
Q

MH reactivity

A

Reactivity. LiH < NaH < KH

with KH more of a mismatched ion pair and
less lattice energy has to be invested for reactions

54
Q

MH reaction with water

A

exothermic reaction

2 MH + 2 H2O → 2 MOH + H2

comproportionation reaction

55
Q

comproportionation reaction?

A

elements with two oxidation states converts to a product with element in one oxidation state

56
Q

alkali metal salt structures?

A

NaCl has face centred cubic structure alternating cations and anion, 6 neighbours

CsCl, CsBr, Csl has primitive cubic structure.

Common for more similarly sized cations and anions, 8 neighbours, ion centre surrounded by 8 opposite charge ions 1:1 ratio

57
Q

alkali metal salts of oxyanions? these are water soluble

A

NO3
- (nitrate), SO42- (sulfate), CO32- (carbonate) and
PO43- (phosphate)

58
Q

Na2CO3 production?

A

Solvay process. used in glass industry

NaCl +. CaCO3 = Na2CO3

59
Q

Lithium salts

A

have large polarisable anions (LiI and LiClO4), these are soluble in ethereal solvents (these include diethyl ether Et2O) where there is attraction between lone pairs

60
Q

[Li(OEt2)4]+ structure

A

central Li corrugated to OEt2 x 4 around in tetrahedral structure

61
Q
A

CH2501 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions