Transcript Ch.41

Ch.41 – s-Block elements
Ch.41 – s-棟元素
A. Characteristic properties of the s-block elements
s-棟元素的特質
1.
1. Metallic character
* s-Block elements have low
low
ionization energies and ______
electronegativities.
They are therefore very electropositive
______ , with a tendency
1.
to lose their outer electrons.
1.金屬性
低
低
*s-楝元素具______電離焓及_____負電性。.
高
所以它們是_____正電性的，有放出外圍電子的趨勢。
* They are all __________They
are silvery coloured and tarnish
metals
rapidly in air.
金屬
* 它們都是_______，銀白色，在空氣中迅速生去光澤。
Group I elements:
Lithium
Rubidium
Sodium
Potassium
Caesium
Calcium
Group II elements:
Beryllium
Strontium
Magnesium
Barium
Radium
* These metals show weaker metallic bonding when compared
with other metals because only one or two valence electrons are
involved in the bonding.
soft
q They are _________
and can be cut with a knife
low melting and boiling points, low hardness
q They have_______
and densities
弱
*它們較其他金屬的金屬鍵_______，因為它們只有一至二顆價
電子作金屬鍵。
軟
q它們質_____，可以被刀切開。
低
q它們具_____熔點、沸點、硬度及密度。
* Group II metals vs Group I metals
*第II族及第I族比較
m.p. / b.p.熔點/沸點
Ⅱ>Ⅰ
Hardness 硬度
Ⅱ>Ⅰ
Density 密度
Ⅱ>Ⅰ
2. Formation of basic oxides and hydroxides
生成鹽基性氧化物及氫氧化物
* The oxides of s-block elements are usually combustion products
of the metals.
s-棟金屬的氧化物通常是其燃燒生成物。
Burning magnesium
2 Mg + O2  2MgO
2 Na + O2  Na2O2
* The hydroxides are usually products of reactions of the
•oxides with water/steam.
•氫氧化物則是氧化物與水/蒸氣反應的生成物。
Na2O + H2O  2NaOH
MgO + H2O  Mg(OH)2
* The oxides and hydroxides of s-block elements are all
basic
_____________
.
鹽基性
* s-棟金屬的氧化物及氫氧化物均屬________。
NaOH  Na+ + OHMgO + 2H+  Mg2+ + H2O
* Basicity of oxides and hydroxides increases down the group.
*氧化物及氫氧化物的鹽基性沿族上至下_________。
增加
3. Bonding type and oxidation state
* The s-block elements form compounds that are predominantly
ionic
__________
in nature.
* They exhibit only one fixed oxidation state in their compounds
q Group I metals : +1
q Group II metals : +2
[Explanation in terms of ionization energies and lattice energies]
3.鍵合類型及氧化態
離子
*s-棟元素的化合物明顯屬_______性。
*它們在化合物中只有一個固定氧化態
q 第I組金屬： +1
q 第II組金屬：
+2
[以電離焓及晶格焓作解釋]
4. Characteristic flame colours of salts鹽的焰色
* Salts of Group I and Group II elements exhibit characteristic
flame colours :
第I及II族元素的鹽呈現獨特的焰色：
Element
Lithium
Sodium
Potassium
Rubidium
Caesium
(a)
Flame Colour
Deep red 深紅
Element
Beryllium
Magnesium
Yellow 黃
Lilac 淡紫
Calcium
(b)
Brick red 磚紅
Strontium
Bluish red 紫紅
Blue藍
Barium
(c)
Flame Colour
_
Blood red 血紅
Apple green蘋果綠
(d)
(a) lithium
(b) sodium
(c) potass
5. Weak tendency to form complexes
低趨勢形成絡合物
e.g. Cu2+ + (aq)  [Cu(H2O)6]2+(aq)
vacant d-orbitals and hence
* Ions of d-block metals have _______________
they can form complexes by ________________
bond formation.
dative covalant
空置的d-軌態
配位鍵
d-楝金屬離子因含_____________，所以可以藉_______形成
絡合物。
* Ions of s-block metals __________
seldom form complexes because
they do not have vacant d-orbitals.
甚少
* s-楝金屬離子因不含空置的d-軌態，故_______形成絡合物。
* Ions of s-block metals may be surrounded by polar solvent
molecules (such as water), with the negative ends of their
solvation
dipoles towards the positive metal ion. This is called _______
of ions (or hydration
__ of ions if water is used as the solvent).
However, such association is just the electrostatic attraction
between the positive ion and the dipoles.
* s-楝金屬離子可能被極性溶劑分子包圍(例如水分子) ，以其
負極指向正金屬離子。這稱為離子的 溶合
_______(若水為溶劑則稱
水合
為_______)。然而，這種諦合祗是正離子與偶極間的靜電引力。
H
O
H
H
Na+ O
H O
H
H
B. Variation in properties of the s-block elements
s-棟元素性質的變化
1. Atomic radii原子半徑
* Variation in atomic radii (metallic radii) and ionic radii :
原子半徑(金屬半徑) 及離子半徑的變化：
•* Ionic radius is always smaller
than atomic radius for Group
I and II elements
小
•*第I及II族元素離子半徑必定______於原子半徑。
* In general, atomic and ionic radii increase
on descending
the groups
增大
* 一般而言，原子及離子半徑沿族由上至下__________。
* Atomic and ionic radii of Group I elements are greater than
Group II elements
大
* 第I族原子及離子半徑________於第II族。
* The pairs of ions _______
Li+ and _______
Mg2+ , or ______
Na+ and
______
Ca2+ have been found to have similar ionic radii.
( diagonal relationship )
+
2+
+
Li
Mg
Na
* _____及_____，_____及_____，兩對離子有相約離子半徑。
Ca2+
(斜向關係)
2. Ionization energies電離焓
* Variation in ionization energies電離焓的變化
* Ionization energies
decrease
on descending both groups
*電離焓沿族由上至下____________。
減小
3. Melting points熔點
* Variation in melting points熔點的變化
In general, the stronger the metallic bond, the
melting point is.
一般而言，金屬鍵越強熔點便________。
越高
higher
__ the
•Factors affecting strength of metallic bond :
•影響金屬鍵強度的因素：
q Size 大小
q No.of valence electrons 價電子數目
q Crystal Structure 晶體結構
* Group II metals have
higher _ melting point than Group I
metals.
* In general, melting points of Group I and II metals _________
decrease
down the groups since the strength of metallic bond decreases
__
on descending both groups
高
*第II族元素熔點比第I族______。
.
減小
*一般而言，第I及II族元素熔點沿族由上至下_______，因金
減弱
屬鍵強度沿族而下_______。
4. Hydration energies of ions 離子的水合焓
M+(g) + (aq)  M+(aq) △Hhyd = -ve
H
H
H
O
O
H
H
Na+
H O
H
H O
H
O
H
H
O
H
* Variation in hydration energies 水合焓的變化
* Magnitudes of hydration energies of the cations _________
decrease
on descending both groups.
減小
* 兩族陽離子的水合焓量值沿族由上至下________。
H
O
H
O
Li+
H O
H
H
O
H
H
H
H
Cs+
O
H O
H
H
* Magnitudes of hydration energies of Group II metal ions are
greater
_______
than Group I metal ions
高
*第II族離子的水合焓量值比第I族為_____。
H
O
Li+
H O
H
H
O
H
H
H H
O
Be2+
H
H O
H
O
H
5. Chemical reactivities
a) General trend in chemical reactivities
* s-Block elements are strong ______________________.
reducing agents
5.化學活潑性
a)化學活潑性的趨勢
還原劑
* s-棟元素是強__________。
M  M+ + e -
* The reducing power
increases
[ Reason ]
增強
* 還原能力沿族由上至下_______。
[原因 ]
M  M+ + e -
down the groups.
M(s) 
M(g) 
M+(g)
On descending the groups, the atomic size increases
_ and hence
increases
(1) tendency to break down the metallic crystal _________
( strength of metallic bond decreases )
(2) tendency to release outermost electron _____________
increases
( ionization energy
decreases )
增加
沿族而下，原子半徑_______，所以
增加
(1) 拆毀金屬晶體的趨勢________。
減弱
(金屬鍵的強度_________。
)
增加
(2) 釋放外圍電子的趨勢________。
減少
(電離烙_______。)
b) Reactions with some substances
(i) Reactions with oxygen/air
* When freshly cut, s-block metals have a bright lustre.
tarnish
However, they _____________
readily when they come into
contact with oxygen in air.
b)與某些物質的反應
(i)與氧/空氣的反應
* 剛切開時，s-棟金屬有光亮的外
觀；然而，接觸空氣中的氧時便很
晦暗
快變_______了
Thus except beryllium and magnesium, the s-clock metals are
paraffin oil
usually stored under __________________
to prevent contact
with the atmosphere. Beryllium and magnesium form a protective
oxide layer and thus tarnish comparatively slowly.
石臘油
故此，除鈹及鎂外，s-棟金屬均儲於_________中以避免接觸
空氣。鈹及鎂因形成氧化物保護層，所以轉晦暗相對較慢。
* All these metals burn brilliantly in air to form one or more of
the three types of oxide.
所有這些金屬均在室氣中閃亮地燃燒生成下列其一或更多的氧化物
。
Combustion products
Metal
Li
2-
Li2O
Na
Rb
Cs
Mg
Ca
Sr
Ba

-
O2
Superoxid
e
Na2O2



K
Be
2-
O
O2
Normal oxide Peroxide
BeO
MgO
CaO
SrO
BaO2
KO2
RbO2
CsO2
(ii)
Reactions with water 與水反應
* Group I metals react with water to give hydrogen gas and
alkaline solutions.
第I族金屬與水反應生成氫氣及鹼性溶液。
e.g. 2 Na
Li reacts with
H2O vigorously
+
2 H2O 
Na reacts with
H2O violently
2 NaOH +
H2
K reacts with
H2O almost
explosively
* The reactivity increases down both groups.
* Group II metals have
lower
reactivity than Group I
metals.
增加
*活潑性沿兩族而下均________。
低
* 第II族金屬比第I族金屬活潑性______。
Ca reacts with H2O readily
at room temperature
(iii) Reactions with hydrogen
* All the s-block metals except beryllium react directly with
hydrides
hydrogen to produce _____________.
(Magnesium requires
high pressure.)
* The reactivity
(iii)
increases
down both groups.
與氫反應
氫化物
*隨鈹外，所有s-楝金屬直接與氫反應生成________。(鎂需
高壓。)
增加
*活潑性沿兩族而下均________。
2Na + H2

2NaH
(iv) Reactions with chlorine
* All s-block metals combine directly with chlorine to produce
chloride
____________.
* e.g.
2 Na + Cl2  2 NaCl
(iv)與氯反應
氯化物
*所有s-楝金屬直接與氯反應生成________。
* e.g.
2 Na
+ Cl2  2 NaCl
Reaction between Na
and Cl
C. Variation in properties of the compounds of s-block elements
1. Reactions of the oxides
* In general, oxides of s-block metals are
in
basic
nature
* Group I oxides are generally
more
basic than Group II
oxides.
* Basicity increases down both groups.
C. s-楝元素化合物性質的變化
1.與氧反應
鹽基性
*一般而言，s-楝金屬的氧化物為________。
高
*第I族氧化物鹽基性比第II族更______。
增加
* 鹽基性沿兩族而下均_________。
* All Group I oxides react exothermically with water to
form hydroxides .
氫氧化物
* 第I族氧化物與水產生放熱反應生成_________。
e.g.
Li2O + H2O  2 LiOH
Na2O + H2O  2 NaOH
2 Na2O2 + 4H2O  4 NaOH + 2H2O2
Dissolution of
Na2O2 in H2O
containing
phenolphthalein
* BeO is _______________.
amphoteric
It is almost insoluble in water or
in acids. Its amphoteric nature is only shown in
hot acids or alkalis :
兩性
* BeO是_______的。它差不多不溶於水及酸。它的兩性只
呈現於與熱的酸或鹼中：
BeO + 2 H+  Be2+ + H2O
BeO + 2 OH- + H2O  Be(OH)42-
•MgO is almost inert towards water, but dissolves in acids to give salts
•MgO與水產不多無反應，但可溶於酸產生鹽：
e.g.
MgO + 2 HCl  MgCl2 + H2O
* Other Group II oxides react readily with water giving slightly alkaline
solutions
其他第II族氧化物與水反應生成輕微鹼性溶液：
e.g.
CaO + H2O  Ca2+ + 2OH-
2. Reactions of the hydrides
* They all react readily with water to give the metal hydroxide
__
hydrogen
and ______________.
.
2.氫化物的反應
氫氧化物 氫氣
*它們均與水反應生成_________及_____。
e.g.
NaH + H2O
 NaOH + H2
CaH2 + 2 H2O  Ca(OH)2 + 2 H2
CaH2 reacts with H2O to
give H2 and OH-
* The reactivity
increases down both groups.
* Group II hydrides are
hydrides.
less
reactive than Group I
增加
* 活潑性沿兩族而下均__________。
低
* 第II族氫化物比第I族金屬活潑性_____。
3. Reactions of the chlorides
soluble
* Chlorides of Group I metals are all readily ______________
in water.
3.氯化物的反應
溶
*第I族金屬氯化物頗______於水。
deliquescent
* Lithium chloride is markedly _______________,
whereas
anhydrous
other Group I chlorides are ___________________.
潮解性
無水
* 氯化鋰是_______的；而其他第I族氯化物則是_____的。
covalent and hence undergoes hydrolysis in
* BeCl2 is ___________
acidic
water giving an ___________
solution.
共價
酸性
* 氯化鈹是______性，所以在水中水解生成______溶液。
BeCl2 + 4H2O  Be(OH)42- + 4 H+ + 2Cl-
* Other Group II chlorides just _____________
dissolve
in water.
溶
*其他第II族氯化物只是_____於水而已。
4. Relative thermal stability of the carbonates and hydroxides
* Thermal stability refers to the decomposition of the
compound on heating.
4. 碳酸鹽及氫氧化物的相對熱穩定性
熱穩定性是指化合物受熱分解情況。
e.g.
MgCO3
 MgO + CO2
Mg(OH)2  MgO + H2O
* The thermal stability of an ionic compound depends
charge and the________of
size
on the _________
the ions.
The attraction between the ions is stronger if the charge
greater
is ________and
the size is smaller .
電荷 大小
* 離子化合物的熱穩定性取決於離子的_____及____。
高
細
若離子的電荷____及尺碼____，離子間的吸力便強。
Li+
K+
F-
F-
On descending a group.as the size of metal ion _______,
increases the
weaker and thus the thermal stability
interionic attraction becomes ________
of the compound becomes ______.
lower
This is true for many ionic compounds of s-block elements , such as
oxides _________
fluorides ets
_______,
增大
沿族而下，金屬離子_____，離子間的吸力轉
弱
下降
_______，所以熱穩定性_________。
很多s-楝元素的離子化合物，例如：________，
氟化物
氧化物
__________均如此。
F- , O2Group Ⅰ,Ⅱ
↑
— stable →
∣
Li+
K+
F-
F-
* However, for _____________
carbonates and _____________,
hydroxides the thermal
increases
stability ______________
on descending the groups.
碳酸鹽 氫氧化物
*然而，________及_________的熱穩定性卻沿族而下______。
增加
CO32-, OH∣
← stable —
↓
* Carbonate and hydroxide are large
_________________
polarizable
anions.
For compounds with such
anions, the thermal stability is
polarizing power
also affected by the _____________________ of the cations.
被極化的大
* 碳酸鹽及氫氧化物是容易____________陰離子。這些陰
離子的化合物，其熱穩定性受陽離子的 極化能力 影響。 .
If the cation has a greater polarising power (i.e. smaller size
greater charge), it will ___________
distort
and ________
the electron
cloud of the neighbouring large anion to a greater extent.
細小
高
若陽離子有強極化能力(i.e. ________及_____電荷),
它會高
扭曲
程度地把相鄰陰離子的電子雲________，
less stable
The compound become _____________ and is more liable to
decomposition to the smaller anions, so that the attraction
between cations and the smaller oxide anions can become
greater.
下降
使其穩定性_______，趨向分解成較細的陰離子，而與陽離
子有更高的引力。
Hence the thermal stability of carbonates and hydroxides of
increases
both Group I and II metals __________________
down the
group.
所以第I及第II族碳酸鹽及氫氧化物的熱穩定性均沿族而下
增加
_________。
Effect of sizes of
cations on thermal
stability of
compounds
* The Group II metal ions are much
smaller than those of
Group I metal ions and have a greater charge
_ . Their polarizing
power is consequently
greater . Carbonates and
hydroxides of Group II metals are therefore
less
than
those of Group I metals.
細小
更高
*第II族金屬離子比第I族_______得多而且電荷______，自
較高
然它們的極化能力______，所以第II族碳酸鹽及氫氧化物比
不穩定
第I族更__________。
2+
l Carbonate碳酸鹽
*All group I carbonates except lithium carbonate can withstand
a temperature around 800oC.
除碳酸鋰外，所有第I族碳酸鹽均能抵受熱力至800oC。
* Lithium carbonate decomposes at around 700oC:
碳酸鋰在700oC左右分解：
Li2CO3(s) 
Li2O(s) + CO2(g)
small size
This is due to the _____________________
of lithium ion,
which leads to a ________________________
and make the
high polarizing power
carbonate unstable.
高極化能力
細小尺碼
這是源於鋰離子的___________而帶來____________，所
以使它不穩定。
Due the high _____________________,
polarizing power
group II carbonates
decompose upon heating:
極化能力
因著高_____________，第II族碳酸鹽受熱均分解：
BeCO3(s)

BeO(s) + CO2(g)
MgCO3(s)

MgO(s) + CO2(g)
CaCO3(s)

CaO(s) + CO2(g)
900oC
SrCO3(s)

SrO(s) + CO2(g)
1290oC
BaCO3(s)

BaO(s) + CO2(g)
100oC
540oC
1360oC
Going down each group, as size of the cation ______________,
increases
the polarizing power _______________,
and hence the
decreases
more stable
carbonates become _____________________.
漸大
沿族而下，因為陽離子________，所以極化能力_______，
較穩定
減弱
故此碳酸鹽變得___________。
l Hydroxide氫氧化物
*All group I hydroxides except lithium hydroxide are stable
when heated.
除氫氧化鋰外，所有第I族氫氧化物受熱時均穩定。
Due the same reasons, lithium hydroxide decomposes upon
heating:
同道理，氫氧化鋰受熱分解：
2 LiOH(s) 
Li2O(s) + H2O(g)
•The group II hydroxides decompose upon heating; its
trend of stability can be revealed from the enthalpy changes:
•第II族氫氧化物受熱分解，其穩定性的趨勢可從焓變
中反映出來：
Be(OH)2 (s)  BeO(s) + H2O(g)
△H = +54 kJ mol-1
Mg(OH)2 (s)  MgO(s) + H2O(g)
△H = +81 kJ mol-1
Ca(OH)2 (s)  CaO(s) + H2O(g)
△H = +109 kJ mol-1
Sr(OH)2 (s) 
SrO(s) + H2O(g)
△H = +127 kJ mol-1
Ba(OH)2 (s)  BaO(s) + H2O(g)
△H = +146 kJ mol-1
5. Relative solubility of the sulphates and hydroxides
硫酸
鹽及氫氧化物的相對溶解度
Enthalpy change of solution
* _________________________________
can be used for
comparing the relative solubility of the ionic compounds.
溶液焓變
_____________________可用作比較離子化合物的相對溶解度。
+ - +
- + + - +
MX(s)
-△Hlattice↘
△Hsoln.
――――→ M+(aq) + X-(aq)
↗△Hhydration
M+(g) + X-(g)
-
+
+
O
+
-
H O
H
H
-
+
+
H
H
O
H
+O
H O
H
H
H
+ - +
- + + - +
MX(s)
-△Hlattice↘
△Hsoln.
――――→ M+(aq) + X-(aq)
↗△Hhydration
M+(g) + X-(g)
+
+
O
+
-
-
+
△Hsoln. = -△H latt +△H hyd
╲╱
╲╱
+ve
-ve
H O
H
H
+
H
H
O
H
+O
H O
H
H
H
* If the magnitude of DHhydration is greater than that of
DHlattice , then DHsolution is negative (exothermic), and
soluble
the compound will, in general, be ___________.
* 若 DH水合 的量值比 DH晶格 高，那 DH溶液 則為負數 (放
熱), 通常該化合物便_________。
溶於水
△Hsoln. = -△H latt +△H hyd
╲╱
╲╱
+ve
-ve
greater
* Group I metal ions have smaller
______ charges and ___
___
sizes than Group II metal ions.
DHlattice of their compounds are smaller __ in magnitude than
those of Group II compounds.
more
DHsolution of Group I compounds is_________
negative .
更低
較大
* 第I族金屬離子比第II族______而且電荷_______。
低
它們的化合物DH晶格 量值比第II族的____。
較大
所以第I族化合物DH
的負值______。
溶液
△Hsoln. = -△H latt +△H hyd
╲╱
╲╱
+ve
-ve
+
+
-
+
-
+
-
2+ - 2+
- 2+ -
+
2+ -
2+
Consequently, sulphates and hydroxides of Group I
soluble than those of Group II
metals are more
___________
metals.
SO42-, OHGroupⅠ> Ⅱ
(all soluble)
全溶
故此，第I族金屬的硫酸鹽及氫氧化物比第II族的
更溶
___________於水。
△Hsoln. = -△H latt +△H hyd
╲╱
╲╱
+ve
-ve
+
+
-
+
-
+
-
2+ - 2+
- 2+ -
+
2+ -
2+
* In comparing within the same group, the________
size
of an
ion is a crucial factor.
大小
*在同一族中比較，離子的________是決定性的因素。
Mg2+
Ca2+
Sr2+
Ba2+
* The hydration enthalpy is dependent on the charge/radius
cation
ratio of the ___________.
sum
The lattice enthalpy is dependent on the _________
of the
radii, i.e. r+ + r-.
陽離子
*水合焓是取決於_______的電荷/半徑比例。
和
晶格焓則取決於陰陽離子半徑之_____i.e.
r+ + r-。
H
+ - +
- + + - +
O
Mg2+
H
O
H O
H
H
H
△Hsoln. = -△H latt. +△H hyd.
╲╱
depends on
r+
╲╱
+
r-
r+
size
* For the hydroxide of Group II metals, the
__________ of
the
same order
anions and cations are of the ___________________ of
magnitude.
* 對 於 第 II 族 金 屬 的 氫 氧 化 物 ， 陽 離 子 及 陰大小
離子的
相約級數
_______-屬___________。
Mg2+ OH-
Ca2+ OH-
Sr2+
OH-
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
OH-
depends on
r+
╲╱
+
r-
r+
less
Down the group, __________
energy is required to break the
lattice as the size of cation increases, but the change in
DHhydration is comparatively small.
較少
沿族而下，因著陽離子增大，拆毀晶格所需之能量_____
，但DH水合 變化則相對較輕微。
Mg2+ OH-
Ca2+ OH-
Sr2+
OH-
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
OH-
depends on
r+
╲╱
+
r-
r+
As a result, DHsolution becomes
negative and
more
the solubility of Group II hydroxides increases down the
group.
增加
結果，DH溶液 的負值_______，第II族氫氧化物溶解度
漸增
沿族而下________。
Mg2+ OH-
Ca2+ OH-
Sr2+
OH-
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
OH-
depends on
r+
╲╱
+
r-
r+
e.g. Solubility of Mg(OH)2
溶解度
< Ca(OH) <
2
Sr(OH)2
< Ba(OH)
OHGroupⅡ↓soluble溶解
Mg2+ OH-
Ca2+ OH-
Sr2+
OH-
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
OH-
depends on
r+
╲╱
+
r-
r+
2
* For the sulphates of Group II metals, since sulphate is a
large anion
_______________,
the cations are much smaller.
大尺碼陰離子
*對於第II族金屬的硫酸鹽，因硫酸根離子屬___________，
陽離子相對較細，
Mg2+
SO42-
Ca2+
SO42-
Sr2+
SO42-
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
SO4
2-
depends on
r+
╲╱
+
r-
r+
*. Down the group, the change in size of the cations does not
cause a significant change in DHlattice ,
沿族而下，陽離子尺碼的改變對 DH晶格 並不構成重要影響；
Mg2+
SO42-
Ca2+
SO42-
Sr2+
SO42-
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
SO4
2-
depends on
r+
╲╱
+
r-
r+
smaller (less negative) (due to
but DHhydration become ______________________
increasing ionic size).
負值減小
但 DH
則 ______________(因為陽離子尺碼增大)
。
水合
H
Mg2+
Ca2+
Sr2+
SO4
SO4
2-
O
H
Li+ 2+
Mg
O
H O
H
H
H
H
H
2+
Cs+
Ba
2-
SO42-
H O
H
△Hsoln. = -△H latt. +△H hyd.
╲╱
Ba2+
SO4
2-
O
H
depends on
r+
╲╱
+
r-
r+
O
H
less negative
As a result, DHsolution becomes ___________________and
the
less soluble
solubility of Group II sulphates ________________
down the group.
負值減小
結果， DH溶液 ___________所以硫酸鹽溶解度沿族而下_______。
減少
Mg2+
SO42-
Ca2+
SO42-
Sr2+
SO42△Hsoln. = -△H latt. +△H hyd.
Ba2+
SO42-
╲╱
depends on
r+
╲╱
+
r-
r+
e.g. Solubility of MgSO4
溶解度
Mg2+
Ca2+
Sr2+
SO42SO4
2-
SO42GroupⅡ
> CaSO > SrSO > BaSO
4
4
4
↑ Soluble
溶解
SO42△Hsoln. = -△H latt. +△H hyd.
Ba2+
SO42-
╲╱
depends on
r+
╲╱
+
r-
r+
D. Uses of the compounds of the s-block elements
saponification
* Sodium hydroxide is used in the _________________
of
fats and oils to produce soap.
D. s-棟元素化合物的用途
* 氫 氧 化 鈉 用 於 脂 肪 及 油 的皂化反應
_______ 中 生 產 肥 皂 。
CH3(CH2)16-COO-CH2
CH3(CH2)16-COO-CH + 3 NaOH  3 CH3(CH2)16 COO-Na+ + CH2—OH
∣
CH3(CH2)16-COO-CH2
CH—OH
∣
CH2—OH
* Sodium hydroxide is also used domestically to clear
blocked drains
________________.
淤塞的喉管
* 氫氧化鈉亦在家居中用於清理____________。
* Sodium carbonate is used in the manufacture of _________.
glass
Soda glass is a mixture of sodium silicate and calcium
silicate, which is made by fusing the carbonate with silica
(from sand)at 1500oC.
玻璃
* 碳酸鈉用於生產________。把碳酸鈉與硅石(來自沙石)
於1500oC 下燒熔，可得到硅酸鈉及硅酸鈣的混合物，這就
是鈉玻璃。
CaCO3 + SiO2 
Na2CO3 + SiO2 
CaSiO3 + CO2
Na2SiO3 + CO2
•* Sodium carbonate is also used in ______________________
sewage treatment
water softening
and _____________________
to precipitate Mg2+ and Ca2+.
污水處理 水的軟化
•*碳酸鈉亦用於__________及_________以沉澱
Mg2+及 Ca2+。
Na2CO3(aq) +
Mg2+(aq)
 MgCO3(s) + 2 Na+(aq)
* Sodium hydrogencarbonate is also used extensively in
Soft drinks
__________________.
飲料
碳酸氫鈉廣泛用於_________中。
* Potassium hydroxide is used for long-lasting
alkaline batteries
__________________________
.
鹼性電池
氫氧化鉀用於__________中。
* Magnesium hydroxide is an active ingredient in antacid such
as ______________________.
milk of magnesia
The magnesium hydroxide
is used to neutralize the excess acid in the stomach.
鎂氧乳
* 氫氧化鎂是制酸劑的有效成份，e.g. ________。氫氧化鎂
可用於中和胃部的過量胃酸。
Mg(OH)2 + 2HCl  MgCl2 + 2 H2O
* Calcium hydroxide (slaked lime ) can be used to neutralize
industrial effluents
the acids in ____________________________
:
*氫氧化鈣(熟石灰) 用於中和_______________的酸性：
工業廢水
Ca(OH)2 + 2H+  Ca2+ + 2 H2O
It can also be spread onto _____________________________
agricultural land
to neutralize the effects of acid rain.
農地
它亦可灑在_________上以中和酸雨的影響。
fireworks
* Strontium compounds are used in _____________because
they will give a persistent and intensive red flame when
burnt.
煙花
* 鍶鹽用來製造________，因為它們燃燒時放出持久及強烈
的紅色火焰。