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Orbital filling tableOrbital filling table
•(1869) Dmitri Mendeleev(Russian chemist) shows a first version of the periodic table. •He noticed that classifying the elements by their atomic mass a periodicity in certain properties could be seen. The first table consisted of 63 elements. •Periodicity: the regular repeating of properties according to the arrangement of elements in the PT.
**Henry Mosely(British) Henry Mosely(British) discovered nuclear charges discovered nuclear charges of all known elements and of all known elements and that chemical properties of that chemical properties of
elements are related to elements are related to their atomic numbers but their atomic numbers but
not atomic weights.not atomic weights.
He stated that elements He stated that elements should be arranged in should be arranged in
order of increasing order of increasing atomic atomic numbersnumbers..
So, today’s periodic table So, today’s periodic table was formed.was formed.
In modern periodic table, In modern periodic table, elements are listed in order elements are listed in order
of increasing atomic of increasing atomic numbers.numbers.
Elements with similar Elements with similar chemical properties are chemical properties are
placed in the same vertical placed in the same vertical columns.columns.
1A:Alkali metals1A:Alkali metals2A:Alkaline earth metals2A:Alkaline earth metals
3A:Earth metals3A:Earth metals4A:Carbon Family4A:Carbon Family
5A:Nitrogen Family5A:Nitrogen Family6A:Oxygen Family6A:Oxygen Family
7A:Halogens7A:Halogens8A:Noble(Inert)gases8A:Noble(Inert)gases
GROUPS/FAMILIES:GROUPS/FAMILIES: The vertical columnsThe vertical columns Elements in the same group have Elements in the same group have -similar chemical properties(exception:-similar chemical properties(exception:H in 1A group)H in 1A group)-Same number of valence electrons-Same number of valence electronsand orbitals.(exception:He in 8A group)and orbitals.(exception:He in 8A group)- The - The effective nuclear charge (effective nuclear charge (the the
charge acting on valence electrons) is charge acting on valence electrons) is the samethe same.(exception:He in 8A group).(exception:He in 8A group)
***For A groups; # of valence *For A groups; # of valence
electrons= # of the group(except electrons= # of the group(except He in 8A)He in 8A)
in 7A;number of valence in 7A;number of valence electrons=7electrons=7
However, we can’t say the same However, we can’t say the same thing for B groups.thing for B groups.
**Lanthanides&Actinides belong to Lanthanides&Actinides belong to 3B group(the biggest group 3B group(the biggest group
including 32 elements)including 32 elements)
PERIODS:PERIODS:
The horizontal rowsThe horizontal rows There are 7 periods There are 7 periods Valence shell determines the period Valence shell determines the period
numbernumber Each of them starts with a metal and Each of them starts with a metal and
ends with a noble gas.(except first ends with a noble gas.(except first and seventh ones)and seventh ones)
Elements in the same period have the Elements in the same period have the same # of energy levels or shells or same # of energy levels or shells or principle quantum numbers.principle quantum numbers.
PERIODIC TRENDS:PERIODIC TRENDS:1)1)ATOMIC&MASS NUMBER:ATOMIC&MASS NUMBER:
AN,MN increases
AN,MN increases
2)2)ATOMIC RADIUS:ATOMIC RADIUS:
Br Br
2r
Radius of an atom: Half the distance between two nuclei.
Covalent radius: Half the distance between two nuclei in a covalent molecule consisting of identical atoms.Van der Waals radius: This is for 0 group gases. Ionic radius: This for ions in an ionic compound.
2)2)ATOMIC RADIUS:ATOMIC RADIUS:
Atomic size (volume,radius) is affected by Atomic size (volume,radius) is affected by mainly two factors in the periodic table:mainly two factors in the periodic table:
1)1)The # of shellsThe # of shells ((as it increases, atomic as it increases, atomic volume also increases) volume also increases)
2)2)Nuclear chargeNuclear charge((as the pas the p++ # increases, # increases, atomic volume decreases)atomic volume decreases)
Li Be B C N O F
Na
Atomic volume decreases
WHY?WHY?
K
1A 2A 3A 4A 5A7A6A
Within the same period;All the elements have the same # of shells but the p+ # increases from left to
right.Therefore,atomic radius decreases from left to right.
Proceeding down a group; The # of shells of atoms increases but the p+ # of atoms also
increases.However,the increase in shells makes a bigger effect on the radius than the nuclear
charge.Therefore, the atomic volume or radius increases down a group.
IONIC VOLUME:
X X+ X+2X-X-2
Less e-e repulsionMore e-e repulsion
For isoelectronic species;The greater the nuclear charge,the smaller the
radius(or volume)
7N-3,8O-2,11Na+,13Al+3 are isoelectronics.The relationship between their radii;
7N-3 >8O-2 >11Na+ >13Al+3
3)IONIZATION ENERGY:The minimum amount of energy
required to remove the most losely bound e-s from a mole of gaseous atoms is called “the
ionization energy(I).”X(g) + I1 X+
(g) + e-
WARNING!!! X2(s)+I1 X+(s) + e-
!!!It’s not the IE(bec. X is a solid
and molecular)
3)3)IONIZATION ENERGY:IONIZATION ENERGY: The energy required to The energy required to
remove (1 mole of) the first remove (1 mole of) the first electron from 1 mole of electron from 1 mole of gaseous atom is called the gaseous atom is called the firstfirst ionization energy. ionization energy.
2)g(2)g( XIX
)g(1)g( XIX
Ionization Ionization EnergyEnergy TheThe second second ionization energy is ionization energy is
the energy required to remove (1 the energy required to remove (1 mole of) the second electron(s).mole of) the second electron(s).
Always greater than first IE.Always greater than first IE. The The thirdthird IE is the energy required IE is the energy required
to remove a third electron.to remove a third electron. Greater than 1st or 2nd IE.Greater than 1st or 2nd IE.
2)g(2)g( XIX
What determines What determines IEIE
The greater the nuclear charge, The greater the nuclear charge, the greater IE.the greater IE.
The greater the effective The greater the effective nuclear charge, the greater IE.nuclear charge, the greater IE.
Greater distance from nucleus Greater distance from nucleus (atomic radius) decreases IE(atomic radius) decreases IE
Shielding of electrons in filled Shielding of electrons in filled inner orbitalsinner orbitals
***Because I of d block elements are irregular, rules that we talk about the IE
belong to A group elements.The variation of first ionization
energies within the same period:As the atomic volume increases, the
attraction of the nucleus on the electrons decreases.
*Ionization energies in the same period:Noble gases > nonmetals > metals
Atomic volume decreases& IE generally increases
Ionization energyIonization energy All the atoms in the same period All the atoms in the same period
have the same energy level.have the same energy level. Same shielding.Same shielding. But, increasing nuclear charge But, increasing nuclear charge
and effective nuclear charge, and effective nuclear charge, ENC.ENC.
So IE So IE generallygenerally increases from increases from left to right.left to right.
***In the same period from left to right the ionization energies:
1A < 3A < 2A < 4A < 6A < 5A < 7A < 8A
irregularitiesThe variation of IE within the same
group:
Down the group, atomic volumes of elements increase and more shielding effect, same ENC.Therefore, the IE of elements decrease in the same group
from top to bottom.
Firs
t Ion
izat
ion
ener
gy
Atomic number
He
He has a greater He has a greater IE than H.IE than H.
same shielding same shielding greater nuclear greater nuclear
chargecharge
H
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li has lower IE than H
Outer electron further away
outweighs greater nuclear charge
Li
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Be has higher IE than Li
Same shielding greater nuclear
charge
Li
Be
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He B has lower IE than Be
B has greater shielding
greater nuclear charge
p orbital is slightly more diffuse and its electron easier to remove
Li
Be
B
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li
Be
B
C
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li
Be
B
C
N
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li
Be
B
C
N
O
Breaks the Breaks the pattern, because pattern, because the outer the outer electron is paired electron is paired in a p orbital and in a p orbital and experiences experiences inter-electron inter-electron repulsion.repulsion.
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li
Be
B
C
N
O
F
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li
Be
B
C
N
O
F
Ne Ne has a Ne has a
lower IE than lower IE than HeHe
Both are full,Both are full, Ne has more Ne has more
shieldingshielding Greater Greater
distancedistance
Firs
t Ion
izat
ion
ener
gy
Atomic number
H
He
Li
Be
B
C
N
O
F
Ne Na has a lower
IE than Li Both are s1
Na has more shielding
Greater distance
Na
Firs
t Ion
izat
ion
ener
gy
Atomic number
Why the drop between groups IIA and IIIA(Be-B)?
The explanation lies with the structures of Boron and Aluminium. The outer electron is removed more easily from these atoms than the general trend in their period would suggest.
Be 1s22s2 1st I.E. = 900 kJ mol-1
B 1s22s22px1 1st I.E. = 799 kJ mol-1
You might expect the Boron value to be more than the Beryllium value because of the extra proton. Offsetting that is the fact that Boron's outer electron is in a 2p orbital rather than a 2s. 2p orbitals have a slightly higher energy than the 2s orbital, and the electron is, on average, to be found further from the nucleus. This has two effects. The increased distance results in a reduced attraction and so a reduced ionisation energy.
The 2p orbital is screened not only by the 1s2 electrons but, to some extent, by the 2s2 electrons as well. That also reduces the pull from the nucleus and so lowers the ionisation energy.
Why the drop between groups IIA and IIIA(Mg-Al)?
The explanation for the drop between Magnesium and Aluminium is the same, except that everything is happening at the 3-level rather than the 2-level.
12Mg 1s22s22p63s2 1st I.E. = 736 kJ mol-1
13Al 1s22s22p63s23px1 1st I.E. = 577 kJ mol-1
The 3p electron in Aluminium is slightly more distant from the nucleus than the 3s, and partially screened by the 3s2 electrons as well as the inner electrons. Both of these factors offset the effect of the extra proton.
If the outer electron looks in towards the nucleus, it doesn't
see the nucleus sharply. Between it and the nucleus there are the two layers of
electrons in the first and second levels. The 11 protons in the sodium's nucleus have their
effect cut down by the 10 inner electrons. The outer electron
therefore only feels a net pull of approximately 1+ from the
centre. This lessening of the pull of the
nucleus by inner electrons is known as screening or
shielding.
Why the drop between groupsVA and VIA (N-O and P-S)?
Once again, you might expect the ionisation energy of the group VIA element to be higher than that of group VA because of the extra proton. What is offsetting it this time?
• 7N: 1s22s22px
12py12pz
1 1st I.E. = 1400 kJ mol-1
8O: 1s22s22px22py
12pz1 1st I.E. = 1310 kJ mol-1
Two electrons in the same orbital experience a bit of repulsion from each other. This offsets the attraction of the nucleus, so that paired electrons are removed rather more easily than you might expect.
The screening is identical (from the 1s2 and, to some extent, from the 2s2 electrons), and the electron is being removed from an identical orbital. The difference is that in the Oxygen case the electron being removed is one of the 2px
2 pair. The repulsion between the two electrons in the same orbital means that the electron is easier to remove than it would otherwise be. The drop in ionisation energy at Sulphur is accounted for in the same way.
Increases
Increases
***We can decide about the group number of A group elements by considering their ionization energy values.Mg(g)(1s22s22p63s2)+I1(176Kcal/mole) Mg+
(g) + e-
Mg+(g)(1s22s22p63s1)+ I2(348Kcal/mole) Mg+2
(g)+ e-
Mg+2(g) (1s22s22p6)+ I3(1847Kcal/mole) Mg+3
(g)+ e-
1st&2nd IE for Mg atom belong to the removal of valence electrons which are bounded very weakly to the nucleus .However,3rd e-
requires considerably more energy than the removal of valence e-s as it will experience higher ENC.
WARNING!!!There is always needed much more energy to remove inner electrons than the outer electrons since the inner electrons will experience a higher ENC.The sharp jumps between ionization energies help us to find out group numbers of A group elements.We can say that Mg atom is in 2A group by considering the sharp increase between its second and third ionization energies.(because,there is very sharp increase between its 2nd&3rd ionization energies)
electron being lost: 1st 2nd 3rd 4th 5th 6th 7th
(2A)(3A)(4A)(5A)(6A)
The rare gases (He, Ne, Ar, Kr, Xe, Rn) appear at peak values of ionization energy, which reflect their chemical inertness, while the alkali metals (Li, Na, K, Rb, Cs) appear at minimum values of ionization energy, in keeping with their reactivity and ease of cation formation.
4)ELECTRON AFFINITY:4)ELECTRON AFFINITY: The electron affinity is the energy The electron affinity is the energy
that is released when an atom in that is released when an atom in the gas phase gains an electron and the gas phase gains an electron and is thus converted to an anion, also is thus converted to an anion, also in the gas phase: in the gas phase:
Electron affinities are difficult to measure and there is no reliable data available for most elements. However, the larger the atom, the lower its electron affinity, as shown with Group VII elements:
For reasons outside the scope of this discussion, the electron affinity of Fluorine is an exception to this trend.
5) 5) ELECTRONEGATIVITY:ELECTRONEGATIVITY:Electronegativity is the Electronegativity is the
power of an atom to attract power of an atom to attract electron density in a electron density in a covalent bond covalent bond (Linus (Linus Pauling)Pauling)
ElectronegativityElectronegativity Electronegativity describes how Electronegativity describes how
electrons are shared in a electrons are shared in a compoundcompound
Consider the compound HClConsider the compound HCl
•The electron clouds represent where the two electrons in the HCl bond spend their time (sizes of atoms are not being shown)
•The shared electrons spend more time around Cl than H. In other words Cl is more electronegative than H.
H Cl
+ –
ElectronegativityElectronegativity
+ – 0 0
H Cl H H
ElectronegativityElectronegativityPauling’s electronegativity scale
H
2.1
He
-
Li
1.0
Be
1.5
B
2.0
C
2.5
N
3.0
O
3.5
F
4.0
Ne
-
Na
0.9
Mg
1.2
Al
1.5
Si
1.8
P
2.1
S
2.5
Cl
3.0
Ar
-
These numbers are derived from These numbers are derived from several factors including EA, IE, atomic several factors including EA, IE, atomic radiusradius
You do not need to understand where You do not need to understand where the numbers come fromthe numbers come from
You need to know that a high number You need to know that a high number means the element has a greater pull means the element has a greater pull on electronson electrons
Calculating EN differencesCalculating EN differences The first step in defining the polarity of a The first step in defining the polarity of a
bond is to calculate electronegativity bond is to calculate electronegativity difference (difference ( EN) EN)
EN = EN large - EN smallEN = EN large - EN small E.g. for NaCl, E.g. for NaCl, EN = 3.2 –0.9 = 2.3, ionic. EN = 3.2 –0.9 = 2.3, ionic.
Bigger electronegativity,Bigger electronegativity,
-Bigger tendency in gaining -Bigger tendency in gaining electrons.electrons.
SummarySummaryShielding is constantAtomic Radius decreasesIonization energy increasesElectronegativity increasesNuclear charge increases
Nu
clear
charg
e
incr
ease
sS
hie
ldin
g i
ncr
ease
sA
tom
ic r
ad
ius
incr
ease
sIo
nic
siz
e i
ncr
ease
sIo
niz
ati
on
en
erg
y d
ecr
ease
sE
lect
ron
eg
ati
vity
d
ecr
ease
s
OXIDATION STATES OF OXIDATION STATES OF ELEMENTSELEMENTS
Group
IA IIA IIIA IVA VA VIA VIIA
VIIIA
MAX(+)
+1 +2 +3 +4 +5 +6 +7 NA
MIN(-)
NA NA NA -4 -3 -2 -1 NA
Important Groups
Groups of Elements•Alkali Metals(IA)(except Fr):
–Group 1A metals –Soft, silvery colored metals that react violently with H2O to form basic solutions
- They have low melting points - They have low melting points and densities and densities due to being the due to being the largest atom in their period of largest atom in their period of the PTthe PT..
Going down the group, the Going down the group, the metals get softer and mp metals get softer and mp decreases due to increase decreases due to increase in atomic size.in atomic size.
•Alkali MetalsAlkali Metals(IA)(IA)(except (except Fr): Fr):
- They are the most reactive of They are the most reactive of
all the metals on the periodic all the metals on the periodic tabletable since they can easily since they can easily lose their one elose their one e..
- Their rectivity also increases Their rectivity also increases as you move down their as you move down their family.Therefore;family.Therefore; most reactive ones are: Cesium & Francium
Because the elements are very Because the elements are very reactive, they easily combine with reactive, they easily combine with water and Oxygen.Therefore, most water and Oxygen.Therefore, most of these elements are not found of these elements are not found freely in nature.That is why they are freely in nature.That is why they are stored in oil in a bottle in the stored in oil in a bottle in the laboratory in order to prevent any laboratory in order to prevent any reaction with Oxygen.reaction with Oxygen.
They tarnish (lose lustre) rapidly They tarnish (lose lustre) rapidly when exposed to the air.when exposed to the air.
Chemical Reactions of Alkali Chemical Reactions of Alkali MetalsMetals
Li KNa
Alkali Metal Family
•They give caharacteristic colour in the flame(chemical peoperty).
Chemical Reactions of Chemical Reactions of Alkali MetalsAlkali Metals
Reaction with oxygen,Reaction with oxygen, React with oxygen to produces oxides.React with oxygen to produces oxides.
44Li(s) + OLi(s) + O22(g) (g) 22LiLi22O(s)O(s)
Chemical Reactions of Chemical Reactions of Alkali MetalsAlkali Metals
Reaction with halogensReaction with halogensReaction with halogens produces saltsReaction with halogens produces salts
2Na(s) + Cl2Na(s) + Cl22(g)(g) 2NaCl(s)2NaCl(s)2K(s) + Br2K(s) + Br22(g)(g) 2KBr(s)2KBr(s)2Cs(s) + l2Cs(s) + l22(g)(g) 2CsI(s)2CsI(s)
Exist as diatomic molecules in which Exist as diatomic molecules in which atoms are joined by a single cov. atoms are joined by a single cov. bond.bond.
The elements in this group are The elements in this group are referred to as Halogens because referred to as Halogens because they produce salts when combined they produce salts when combined with alkali metalswith alkali metals (e.g. (e.g.NaCl)NaCl).these .these salts are usually white & soluble in salts are usually white & soluble in water.water.
•HALOGENS(VIIA)HALOGENS(VIIA) except Atexcept At::
They are all very reactiveThey are all very reactive and quite and quite electronegativeelectronegative nonmetals nonmetals. The ease . The ease w/ which they gain electrons w/ which they gain electrons decreases going down the group.decreases going down the group.
Halogens tend to be Halogens tend to be lessless reactive as reactive as you move down the group.you move down the group.FlourineFlourine is is the most reactive Halogen and the most reactive Halogen and combines with other elements very combines with other elements very readily.readily.
Oxidizing power decreases down the Oxidizing power decreases down the group.group.
•HALOGENS(VIIA)HALOGENS(VIIA) except Atexcept At::
Most are Poisonous Most are Poisonous .. When Fluorine combines with Na to When Fluorine combines with Na to
form NaF,it is an effective cavity form NaF,it is an effective cavity fighter that is added to fighter that is added to toothpastes.toothpastes.
Chlorine is a great bacteria fighter Chlorine is a great bacteria fighter so it is used in swimming pools and so it is used in swimming pools and household cleaning agents.household cleaning agents.
Iodine is also useful for eliminating Iodine is also useful for eliminating bacteria.Since it is not as reactive bacteria.Since it is not as reactive as Chlorine, it can be used on as Chlorine, it can be used on humans.humans.
Going down the group, their physical state Going down the group, their physical state varies at room temp & pressure depending varies at room temp & pressure depending on the Van Der Waals force strength on the Van Der Waals force strength present between molecules since the present between molecules since the molecules have different molecular mass molecules have different molecular mass values.values.
FF22, Cl, Cl22 -- -- gas gas BrBr22 --- --- liquid liquid II22 -- -- solid, forms a purple gas on heating. solid, forms a purple gas on heating. They all need an electron to become stable, They all need an electron to become stable,
thus form negative ionsthus form negative ions
•HALOGENS(VIIA)HALOGENS(VIIA) except Atexcept At::
Are slightly soluble in water as they Are slightly soluble in water as they are non-polar molecules.are non-polar molecules.
Concentrated solutions of chlorine-Concentrated solutions of chlorine- green tingegreen tinge
Solutions of bromine-Solutions of bromine- darken from darken from yellow through orange to brown as the yellow through orange to brown as the concentration increases.concentration increases.
Iodine dissolved in non-polar solvents Iodine dissolved in non-polar solvents like hexane--like hexane--violet solution.violet solution.
Iodine dissolved in polar solvents like Iodine dissolved in polar solvents like water & ethanol--water & ethanol--brown solution.brown solution.
•HALOGENS(VIIA)HALOGENS(VIIA) except Atexcept At::
Halogens dissociate slightly in aqueous Halogens dissociate slightly in aqueous solutions, forming an acidic solution:solutions, forming an acidic solution:
ClCl22(aq) + H(aq) + H22O(l) O(l) H H++ (aq)+ Cl (aq)+ Cl--(aq) + (aq) + HOCl(aq)HOCl(aq)
HOCl(hypochlorous acid): weak acid, reacts as HOCl(hypochlorous acid): weak acid, reacts as an oxidant since it donates its one oxygen.It an oxidant since it donates its one oxygen.It oxidises colored dyes to colorless products.oxidises colored dyes to colorless products.
HOCl turns blue litmus paper into red, and HOCl turns blue litmus paper into red, and then make it colorless. Therefore, HOCl and then make it colorless. Therefore, HOCl and OClOCl-- are used in bleaches.They are also toxic are used in bleaches.They are also toxic to microbes.to microbes.
•HALOGENS(VIIA)HALOGENS(VIIA) except Atexcept At::
Displacement reactions of Displacement reactions of HalogensHalogens
A more reactive halogen A more reactive halogen is capable of replacing is capable of replacing less reactive one from less reactive one from
its solutionits solution
ClCl22 reacts with Br reacts with Br-- and I and I-- ClCl22(aq)(aq) + 2Br + 2Br--(aq)(aq) 2Cl 2Cl--(aq)(aq) + +
BrBr22(l)(l)
ClCl22(aq)(aq) + 2I + 2I--(aq)(aq) 2Cl 2Cl--(aq)(aq) + I + I22(s)(s)
BrBr22 reacts with I- reacts with I-BrBr22(aq)(aq) + 2I + 2I--(aq)(aq) 2Br 2Br--(aq)(aq) + I + I22(s)(s)
II22 non-reactive non-reactive with halide ions with halide ions
84
The common insoluble halides (ions of The common insoluble halides (ions of halogens) are those of Pb and Ag.halogens) are those of Pb and Ag.
PbIPbI2 2 ---- is a bright yellow colored, can is a bright yellow colored, can be used as a test for iodide ion.be used as a test for iodide ion.
Look at P. 77 Look at P. 77
& 78 for the colors of & 78 for the colors of
halogens and tests halogens and tests
of halide ions.of halide ions.
•HALOGENS(VIIA)HALOGENS(VIIA) except Atexcept At::
Oxides of period 3 elementsOxides of period 3 elements
Metallic Oxides in Period 3Metallic Oxides in Period 3
Sodium oxide: NaSodium oxide: Na22OO ionicionic
Magnesium oxide: MgOMagnesium oxide: MgO ionicionic
Aluminum oxide: AlAluminum oxide: Al22OO33 ionicionic
Metalloid oxide in Period 3Metalloid oxide in Period 3
Silicon dioxide: SiOSilicon dioxide: SiO22 covalentcovalent
Nonmetallic oxides in Period 3Nonmetallic oxides in Period 3
Tetraphosphorus decoxide: PTetraphosphorus decoxide: P44OO1010 covalentcovalent
Sulfur trioxide: SOSulfur trioxide: SO33 covalentcovalent
Dichlorine heptoxide: ClDichlorine heptoxide: Cl22OO77 covalentcovalent
86
Discuss the changes in nature, from Discuss the changes in nature, from ionic to covalent and from basic to ionic to covalent and from basic to
acidic, of the oxides across period 3.acidic, of the oxides across period 3.
Acidic/BasicAcidic/BasicMetallic oxides in Period 3 are basicMetallic oxides in Period 3 are basicSodium oxide: Sodium oxide: NaNa22O + HO + H22O O 2 NaOH 2 NaOH
basicbasicMagnesium oxide: Magnesium oxide: MgO + HMgO + H22O O Mg(OH) Mg(OH)22 basicbasic
Net ionic eqn: ONet ionic eqn: O2-2- + H + H22O O 2 OH 2 OH--
Aluminum oxide: Aluminum oxide: AlAl22OO33 + 6HCl + 6HCl 2 AlCl 2 AlCl33+ 3H+ 3H22O O amphotericamphoteric
AlAl22OO33 +2 NaOH + 3H +2 NaOH + 3H22O O 2NaAl(OH) 2NaAl(OH)44
87
Oxides of period 3 Oxides of period 3 elementselements
Metalloid oxide in Period 3 is acidicMetalloid oxide in Period 3 is acidicSilicon dioxide:Silicon dioxide: SiOSiO22 + H + H22O O H H22SiOSiO33 acidicacidic
(silicic acid) (silicic acid)
Nonmetallic oxides in Period 3 are acidicNonmetallic oxides in Period 3 are acidicTetraphosphorus decoxide: PTetraphosphorus decoxide: P44OO1010 + 6H + 6H22O O 4H 4H33POPO44 acidicacidicSulfur trioxide: Sulfur trioxide: SOSO33 + H + H22O O H H22SOSO44
acidicacidicDichlorine heptoxide: Dichlorine heptoxide: ClCl22OO77 + H + H22O O 2HClO 2HClO44 acidicacidicArgon does not form an oxideArgon does not form an oxide
Look at!!Look at!!
P.80P.80
