topic 4 bonding . sl + hl
DESCRIPTION
Topic 4 Bonding . SL + HL. Ionic bond Covalent bond Intermolecular forces Hydrogen bond Dipole-dipole attraction van der Waals’ forces Metallic bond. 4.1 Ionic bond. Ions = charged particles Ionic bond= the electrostatic bond between positively and negatively charged ions - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/1.jpg)
Topic 4 Bonding.
SL + HLIonic bond
Covalent bondIntermolecular forces
Hydrogen bondDipole-dipole attraction
van der Waals’ forcesMetallic bond
![Page 2: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/2.jpg)
4.1 Ionic bond
Ions = charged particlesIonic bond= the electrostatic bond between positively and negatively charged ionsIonic compound= a compound built from ions, i.e. a salt
![Page 3: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/3.jpg)
• Atoms want to get a “Noble gas electron configuration”. One way to get that structure is to throw away the valence electron or steal some electrons to get a full outer shell.
![Page 4: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/4.jpg)
• Sodium gives one electron to chlorine and both will have noble gas configuration. Which noble gas?
• Sodium ion: positive electric charge. Cation.Chloride ion: negative electric charge. Anion.
Na + Cl Na+ + Cl-
2,8,1 2,8,7 2,8 2,8,8
![Page 5: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/5.jpg)
Ionic crystals• + charge particles and – charge particle
attracts each other in three dimension and builds up a lattice/crystal. Strong electrostatic forces in three dimensions. Each cation is surrounded by anions and vice versa.
![Page 6: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/6.jpg)
Ions
• Group 1: H+, Li+, Na+, K+, Rb+, Cs+, Fr+
• Group 2: Be2+, Mg2+, Ca2+, Sr2+, Ba2+
• Group 3?/13: B3+, Al3+, Ga3+
• Group 6?/16: O2-, S2-, • Group 7?/17: F-, Cl-, Br-, I-
![Page 7: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/7.jpg)
Naming compounds
• Positive ions have the name of the atom: Sodium ion
• Negative ions have the name of the atom (or almost) + the ending –ide: Chloride ion
• Sodium + chlorine Sodium chloride• Lithium + oxygen Lithium oxide
![Page 8: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/8.jpg)
Formula of ionic compounds
Na+ Mg2+ Al3+
Cl-
O2-
N3-
Write the chemical formula of the compounds formed between the positive and negative ions above.Write the name of the ionic compounds
![Page 9: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/9.jpg)
Transition metals
• Transition metals can often form more than one ion, e.g.:– Fe2+ and Fe3+
– Cu+ and Cu2+
• HL: coloured because of d-orbitals
![Page 10: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/10.jpg)
Some common polyatomic ions
• Nitrate NO3-
• Hydroxide OH- • Sulphate SO4
2-
• Carbonate CO32-
• Hydrogen carbonate HCO3-
(Bicarbonate)
• Phosphate PO43-
• Ammonium NH4+
Ca(OH)2
![Page 11: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/11.jpg)
Formula of ionic compounds-2
Na+ Mg2+ NH4+
OH-
SO42-
PO43-
Write the chemical formula of the compounds formed between the positive and negative ions above. Write the name of the ionic compounds
![Page 12: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/12.jpg)
When can we expect an Ionic bond?
• The quick rule: Metal + non-metal => Ionic compounds
(Salts)
CuSO4 (s)
![Page 13: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/13.jpg)
Electronegativity
• Electronegativity is a measure of an atoms power to attract electrons.
• On the right side in the periodic table (group 7,6,5) the atoms have high values, they attract electrons readily. Best is Fluorine, e-neg 4.
• On the left side the values are low. Low ability to attract electrons.
![Page 14: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/14.jpg)
Electronegativity values
FONClBrISCH
![Page 15: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/15.jpg)
Ionic bond or not- calculate difference in electronegativity
• If you want to do a more “precise” estimation you can calculate it with the help of electronegativity values.
• If the difference in electronegativity > 1,7 then you can say it's an Ionic bond.
![Page 16: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/16.jpg)
Ionic bond or not?Use electronegativity values in the Chemistry Data booklet
• NaCl• MgO• AlCl3
• SiO2
• Ca3N2
![Page 17: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/17.jpg)
Typical properties of Salts
Hard, brittle, • Conduct electricity in solution or melted • High melting points => Strong bond• Hydration of Ion in Water solution
![Page 18: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/18.jpg)
4.2 Covalent bond
Electron pair bond, molecular bond
• If the De-neg < 1,7 the bond is considered to be covalent
• Often between non-metals• Polar or non-polar
![Page 19: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/19.jpg)
• In a covalent bond the atoms share electrons with
each other to get a “Noble gas electron configuration”
• The bond has a direction (one atom to an other atom)
• One bond consists of two electrons, an electron pair
OH H
![Page 20: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/20.jpg)
• Single bond: the two atoms share two electrons (1 pair)
• Double bond: the two atoms share four electrons (2 pairs)
• Triple bond: the two atoms share six electrons (3 pairs)
![Page 21: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/21.jpg)
Lewis structures
• all valence electrons marked by dots or lines. Draw Lewis structures for:
• F2
• NH3
• CO2
• N2
• C2H4
![Page 22: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/22.jpg)
Number of bonds bond lengths and bond strengths
• As the number of shared electrons increase (single to triple) the bond lengths shortens and the bond energy increase
Bond Bond type Lengths (pm) Energy (kJ/mol)CC Single 154 347
CC Double 134 614
CC Triple 120 839
-COOH Single 143 358
-COOH Double 123 745
![Page 23: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/23.jpg)
Non-polar covalent bond
• In, for example, H2 the two electrons in the bond are shared equally between the two hydrogen atoms
• H-H De-neg =0
• The electron distribution is symmetrical
![Page 24: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/24.jpg)
Polar covalent bond
• If two different atoms form a covalent bond there will be a difference in De-neg
• The atom with highest electronegativity will have the electrons closer; they don’t share equally
• Unsymmetrical electron distribution
![Page 25: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/25.jpg)
• Which molecules contains at least one polar covalent bond?
F2 HF NF3 SiF4
• Which bond in the pairs below have the highest polar character?
a) C-O, N-Ob) H-O, S-Oc) H-O, H-Sd) Se-S, Se-F
![Page 26: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/26.jpg)
Ionic, polar or non-polar covalent bond?
• % ionic character of a bond: 0-90%(there are no 100% ionic compounds)
Na+ Cl-H-ClCl-Cl
![Page 27: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/27.jpg)
Dative covalent bond
• In a “normal” covalent bond both atoms contribute with electrons to the bond.
• Sometimes only one atom contributes with both electrons (the electron pair) to the bond
• Then the covalent bond is called a dative covalent bond
![Page 28: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/28.jpg)
Examples of dative bonds
• H2O + H+ H3O+
• NH3 + H+ NH4+
• C (4 ve-)+ O (6 ve-) CO
![Page 29: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/29.jpg)
VSEPR
• Valence Shell Electron Pair Repulsion
• Shape and bond angles • Determine the molecules structure, the shape in 3
dimensions• Structure around a given atom is determined principally
by minimising electron-pair repulsion
• Bonding or non-bonding pairs will be as far apart as they can.
![Page 30: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/30.jpg)
Linear
• Two negative centers• 180o • E.g. CO2
![Page 31: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/31.jpg)
Trigonal planar (flat)
• Three negative centers• 120o • E.g. BF3
![Page 32: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/32.jpg)
Tetrahedral arrangement
• Four negative centers• 109.5 o
![Page 33: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/33.jpg)
Method
1. Draw Lewis structure2. Count electron pairs, minimise the repulsion3. Positions of the atoms4. Name of the structure
![Page 34: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/34.jpg)
Ammonia, NH3 Tetrahedral, Trigonal planar 107o, one non-bonding electron pair
• Non-bonding pair (lone pair) takes more space => reduce bond angels
![Page 35: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/35.jpg)
Water, H2O Tetrahedral, Non-linear (bent) 104o Two non-bonding electron pairs
Non-bonding pair (lone pair) takes more space => reduces bond angles
![Page 36: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/36.jpg)
![Page 37: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/37.jpg)
Non-polar and polarmolecules (dipoles)
• Based on bond polarity and molecular shape • May predict how a molecule will behave with
other compounds• Polar molecule = Dipole
![Page 38: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/38.jpg)
A polar molecule (a dipole)• Must have polar covalent bonds.
– Look at the difference in electronegativity.FONClBrISCH
AND• Unsymmetrical shape according to charge distribution.
• Otherwise it will be a non-polar molecule (NOT a dipole)
![Page 39: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/39.jpg)
![Page 40: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/40.jpg)
Dipole or not?
• H2O
• CO2
• NH3
• CH4
• CH3OH
![Page 41: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/41.jpg)
Allotropes
• Some elements can be found in different forms
• E.g: – Carbon: Diamond, graphite, C60fullerene– Oxygen, Ozone
See PPT: Carbon allotropes
![Page 42: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/42.jpg)
Silicon
• Metalloid, Semiconductors, non-metallic structure
• Similar structure as diamond
![Page 43: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/43.jpg)
Silicon dioxide• SiO2 Silica, giant structure similar to diamond, quarts
• Silicates, NaSiO4, tetrahedrical, silicon-oxygen single bond
![Page 44: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/44.jpg)
![Page 45: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/45.jpg)
4.3 Intermolecular forces • Holds molecules together in liquids or solids (No
Intermolecular forces between gaseous particles)
• Weaker than covalent and ionic bonds
• Hydrogen bond (Quite strong)• Dipole-dipole (Middle weak)• van der Waal’s forces (~ London dispersion forces)
(Very weak)
• Accounts for differences in aggregatio state and solubility
![Page 46: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/46.jpg)
van der Waal’s forces• “Vibrations” in the electron cloud => Temporary
dipoles.
• A temporary dipole in one molecule can induce a temporary dipole in another molecule
• Exist between all molecules
![Page 47: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/47.jpg)
• The strength increases with molar mass of the molecule/atom
E.g. He b.p 4 K Xe b.p. 165 K
• Only effective over short range so the molecule “area” is also important.
E.g: Pentane, C5H12, b.p. 309 KDimethylpropane, (CH3)4C b.p. 283 K
van der Waal’s forces, cont.
![Page 48: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/48.jpg)
Dipole-dipole bond• Electrostatic attraction between molecules
with permanent dipoles• Stronger than van der Waals bond
Hydrogen chloride M= 36,5 g/mol b.p. 188 K
Fluorine M= 38 g/mol b.p. 85K
![Page 49: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/49.jpg)
Hydrogen bond• In molecules that contain Hydrogen bonded to
Oxygen, Nitrogen or Fluorine (high electronegativity and non-bonding electron pair)
• Stronger than dipole-dipole bonds
• Interaction of the non-bonding electron pair in one molecule and hydrogen (with high positive
charge) in another molecule.
![Page 50: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/50.jpg)
Which intermolecular bond?• H2O b.p.= 100oC H2S b.p.= -61oC
• NH3 b.p.= -33 oC PH3 b.p.= -88oC
![Page 51: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/51.jpg)
Which intermolecular bond?
• C2H6 b.p. CH3CHO C2H5OH b.p. -89 oC 20 oC 78 oC
![Page 52: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/52.jpg)
Boiling points of hydrogen compounds
![Page 53: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/53.jpg)
What kind of intermolecular bonds can be expected to dominate between the molecules/atoms?a) NH3(l)b) C5H12(l) c) Br2(l) d) HI(I) e) Ar(l) f) PCl3(l) g) CH3OH(l) h) CHCl3(l)
![Page 54: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/54.jpg)
4.4 Metallic bonding
• Metals have low electronegativity• The atoms are packed close together in a
lattice• The valence electrons are delocalised among
all atoms.– The valence electron have no “home”– The atoms can be seen as positive ions in a see of
electrons that keep them together
![Page 55: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/55.jpg)
![Page 56: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/56.jpg)
This can explain the metallic properties• Electrical conductivity: electrons float around.
If you put in one, one will fall out.• Malleability (smidbarhet) and Ductility
(sträckbarhet): if the atom is pushed from it’s location the electron will follow. The bond is between the ion and the electrons not between the ions.
![Page 57: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/57.jpg)
Summary• The different kind of bonds is very important
for the behaviour of a compound, solution or a mixture
![Page 58: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/58.jpg)
4.5 The strength/type of the bond affects:
• Melting points (impurities lower the melting point)
• Boiling points• Volatility (how easy a compound will convert
to gas)• Electrical conductivity• Solubility and miscibility
![Page 59: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/59.jpg)
Fe (s) Fe (l) Fe (g)
NaCl (s) NaCl (l) NaCl (g)
Which bonds are broken?Which bond is strongest?
Changes in state (1)1538 ºC 2861 ºC
801 ºC 1413 ºC
![Page 60: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/60.jpg)
H2O (s) H2O (l) H2O (g)
HCl (s) HCl (l) HCl (g)
CH4 (s) CH4 (l) CH4(g)
Which bonds are broken?Which bond is strongest?
Changes in state (2)0 ºC 100 ºC
-85 ºC -61 ºC
-162 ºC-184 ºC
![Page 61: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/61.jpg)
• Molecules with van der Waals bonds
Solubility
• Unpolar compounds • Polar compounds• Ionic bonds• Molecules with
hydrogen bonds • Molecules with
dipol-dipol bonds
![Page 62: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/62.jpg)
Intermolecular bonds in solutions• Ion-hydrogen bonds or ion-dipole bonds
![Page 63: Topic 4 Bonding . SL + HL](https://reader030.vdocument.in/reader030/viewer/2022012317/56815c8c550346895dca9c49/html5/thumbnails/63.jpg)
Structure typeProperty
GiantMetallic
GiantIonic
GiantCovalent
MolecularCovalent
Hardness and malleability
Variable hard-ness, malleable rather than brittle
Hard and brittle
Hard and brittle
Usually soft and malleable unless hydrogen bonded
Melting and boiling points
Variable dep. On No of valence e-
High Very High Low
Electrical and thermal conductivity
Good in all states
Not as solids, conduct in (aq) or (l)
No No
Solubility
Insoluble, except as alloys
In Water mostly
Insoluble Often more soluble in other than water except if H-bonded
Examples Iron, copper NaCl, Na2SO4 Diamond,SiO2 (Sand)
CO2, Cl2, ethanol, sugar