CHEMISTRY FORM 4 KSSM CHAPTER 5 : CHEMICAL BONDS

1. PREPARED BY : ESTHER ANNE ANAK RANDI
CHAPTER 5
CHEMICAL BONDS

2. 5.4.1 Explain with examples the formation
of hydrogen bond
 State the meaning of hydrogen bond
 Explain formation of hydrogen bond
 Illustrate the formation of hydrogen bond
5.4 Hydrogen Bond

3. HYDROGEN BOND
• Hydrogen bond is an electrostatic force of attraction that exists when a hydrogen atom is bonded to
an electronegative atom such as nitrogen, oxygen or fluorine (N, O or F).
• For example : hydrogen bonds exists between water, H2O molecules and between ammonia, NH3
molecules.

4. HYDROGEN BOND
• Hydrogen bond : attraction forces between hydrogen atom, H that has bonded with an atom of
high electronegativity, such as nitrogen, N, oxygen, O or fluorine, F with nitrogen, N, oxygen, O or
fluorine, F in another molecule.
• For example, water molecule, H2O can form hydrogen bonds among water molecules, H2O.

5. HYDROGEN BOND
• Oxygen atom has high electronegativity. Water
molecule, H2O is made up of one oxygen atom and two
hydrogen atoms. Hydrogen atoms, H and oxygen atom,
O are bonded by sharing of electrons (Covalent bond).
• The attractive force generated between H atom in
one water molecule and O atom in another water
molecule forms a hydrogen bond.
• In general, hydrogen bond is described as X-H….Y, in
which X and Y symbolizes highly electronegative
atoms (N, O or F) and the three dots (…) symbolizes
hydrogen bond.

6. ROLE OF HYDROGEN BOND IN DAILY LIFE
• There are protein molecules that form hydrogen bonds among one another in the hair structure.

7. ROLE OF HYDROGEN BOND IN DAILY LIFE
• When hair is wet, protein molecules no longer form hydrogen bonds among themselves.
• Instead, protein molecules will form hydrogen bonds with water molecules, H2O.
• Water molecules, H2O will also form hydrogen bonds with other hair protein molecules.
• This causes hair to stick together

8. HYDROGEN BOND
Explain the formation of ammonia molecules, NH3 based on the diagram below.
- N atom has high electronegativity.
- NH3 molecule is made up of one N atom and three H atoms.
- H atoms and N atom are bonded by sharing of electrons (covalent bond).
- The attractive force generated between H atom in one NH3 molecule and N atom in another NH3 molecule is
known as hydrogen bond.

9. ROLE OF HYDROGEN BOND IN DAILY LIFE
• Have you ever come across the problem of turning the pages of a book where the pages stick together?
• To overcome this problem, you lick your finger before turning the pages.
• Why does a wet finger help to turn the pages of a book?

10. 5.4.2 Explain the effect of the hydrogen bond
on the physical properties of substances
5.4 Hydrogen Bond

11. EFFECT OF HYDROGEN BONDS ON THE PHYSICAL PROPERTIES OF SUBSTANCES
Boiling point of ethanol
• Compounds in the form of liquids reach boiling point when the attraction forces between molecules are
overcome
• In the covalent compound of ethanol, C2H5OH, there are hydrogen bonds formed between molecules,
other than weak Van der Waals attraction forces.
• Strong hydrogen bonds are difficult to break. More heat energy is required to overcome the weak Van
der Waals attraction forces, besides breaking the hydrogen bonds.
• As a result, the boiling point of ethanol, C2H5OH is high.
On the other hand, molecules like chlorine, Cl2 which do
not form hydrogen bonds have lower boiling point
compared to ethanol.

12. EFFECT OF HYDROGEN BONDS ON THE PHYSICAL PROPERTIES OF SUBSTANCES
Solubility of ethanol in water
• Ethanol, C2H5OH is also soluble in water. The solubility of ethanol, C2H5OH in water is due to the
formation of hydrogen bonds between the ethanol molecule, C2H5OH and water molecule, H2O.

13. Test Yourself 5.4 (textbook, page 119)
• State the meaning of hydrogen bond?
• Hydrogen fluoride, HF exists as liquid in room temperature. Explain this phenomenon
based on the formation of hydrogen bonds.
• Can hydrogen bonds form among hydrogen chloride molecules, HCl? Justify your answer.
• Explain why paper sticks together when wet.

14. Test Yourself 5.4 (textbook, page 119)
• State the meaning of hydrogen bond?
The attraction force between hydrogen atom, H bonded to highly electronegative atoms,
such as nitrogen, N, oxygen, O or fluorine, F with nitrogen atoms, N, oxygen, O or fluorine,
F in other molecules.

15. Test Yourself 5.4 (textbook, page 119)
• Hydrogen fluoride, HF exists as liquid in room temperature. Explain this phenomenon
based on the formation of hydrogen bonds.
Hydrogen fluoride molecule, HF consists of one hydrogen atom, H and one fluorine atom, F.
Fluorine atom has high electronegativity.
The attraction force is formed between the hydrogen atom that is bonded to the fluorine atom
in one molecule with a fluorine atom in another hydrogen fluoride, HF molecule.
A strong hydrogen bond is formed.
A lot of heat energy is required to overcome the attractive van der Waals forces between the
hydrogen fluoride molecules in addition to the hydrogen bonds.
Hence, hydrogen fluoride has high boiling point and exists as liquid at room temperature.

17. Test Yourself 5.4 (textbook, page 119)
• Can hydrogen bonds form among hydrogen chloride molecules, HCl?
Justify your answer.
No. Even though chlorine atom has high electronegativity, its size is too large.

18. Test Yourself 5.4 (textbook, page 119)
• Explain why paper sticks together when wet.
• Cellulose in paper has oxygen atom bonded to hydrogen atom. Water molecules will form
hydrogen bonds with cellulose in paper. Thus, paper stick together when wet .

19. 5.5.1 Explain with examples the formation
of dative bond
 State the meaning of dative bond
 Explain formation of dative bond
 Illustrate the formation of dative bond
5.5 Dative Bond

20. ● Dative bond or coordinate bond is a type of covalent bond where the electron pair that is
shared comes from one atom only.
DATIVE BOND

21. DATIVE BOND
- A dative bond or a coordinate bond is a type of covalent bond formed when both of the electrons shared
between the two atoms comes from only one of the atoms.
- Example : Ammonium ion, NH4
+ and hydroxonium ion, H3O+
- Dative bond is usually illustrated by an arrow from the direction of the atom that provide the electron
pair (donor atom) to the acceptor atom.
Free pair of
electrons
Dative bond
Free pairs/ Lone pairs refers to a pair of valence electrons that are not shared with another atom in a covalent bond and is
sometimes called an unshared pair or non-bonding pair. Lone pairs are found in the outermost electron shell of atoms. They
can be identified by using a Lewis structure.

22. DATIVE BOND
- In ammonia molecule, NH3, the nitrogen atom, N achieved the stable octet electron arrangement whereas
hydrogen atom, H achieve the stable duplet electron arrangement,
- The hydrogen ion, H+ has no electron in its shell.
- The free electron pair, which is not involved in the formation of covalent bond in NH3 molecule, is shared
with the H+ ion through the formation of a dative bond.
- In the ammonium ion, NH4
+, N atom and H atoms all achieved the stable octet and duplet electron
arrangements.

23. ● Formation of dative bond in hydroxonium ion, H3O+
DATIVE BOND

24. DATIVE BOND
Explain the formation of hydroxonium ion, H3O+ based on the diagram below.
- In H2O molecule, O atom achieved the stable octet electron arrangement whereas H atom achieved the
stable duplet electron arrangement.
- H+ ion has no electrons in its shell.
- The free electron pairs which is not involved in the formation of covalent bond in H2O molecule is shared
with the H+ ion through the formation of a dative bond.
- In H3O+ ion, O atom and H atoms all achieved the stable octet electron and duplet electron arrangement,

25. DATIVE BOND
Representing dative bonds
● In simple diagrams, a dative bond is shown by an arrow.
● The arrow points from the atom donating the lone pair to the atom accepting it.
Dative bond

26. 5.6.1 Explain the formation of a metallic bond
5.6.2 Reason out the electrical conductivity of
metal
 Explain the formation of metallic bond
 Give reason to the electrical conductivity of metal
5.5 Metallic Bond

27. ● Metallic bond is the strong electrostatic force between the sea of electrons and the
positive metal ion.
● Metallic bond are formed from the strong electrostatic attraction between negatively-
charged sea of electrons and fixed, positively-charged metal ions.
● In metal, atoms are packed closely together in regular arrangement. The metal is in solid form.
Metal atoms tend to lose their valence electrons and become positively-charged ions.
● The valence electrons from the metallic atom are free to move throughout the metal
structure (metal lattice structure). These mobile electrons are called delocalized electrons.
METALLIC BOND

28. ● Metals are electropositive atoms in which their valence electrons are removed easily.
● The valence electrons of the metal electrons are delocalized to form a sea of electrons.
● Thus, an electrostatic attractive force exists between the sea of electrons and the positively-
charged metal ion forming the metal bond.
● Metals can conduct electricity because the electrons in the sea are free electrons which carry
charges.
METALLIC BOND
Metal atoms
Sea of electrons

29. ● Metal atoms are arranged closely packed and orderly in
the solid state.
● Valence electrons of metal atoms can be donated easily
and delocalised although in the solid state.
● Metal ions that are positively-charged are formed when
valence electrons are delocalised.
METALLIC BOND

30. ● All delocalised valence electrons can move freely between the metal structure
and form a sea of electrons.
● Electrostatic attraction force between the sea of electrons and the positively-
charged metal ions form the metallic bond.
METALLIC BOND

31. ● When electrons of metal atoms are delocalised in the sea of electrons, the metal
can conduct electricity.
● Electrons that move freely in the metal structure carry the charges from the negative
terminal to the positive terminal when electricity is supplied
METALLIC BOND

32. Which of the following is not affected by a hydrogen
bonding?
A H2O
B NH3
C HCl
D HF
Hydrogen Bond, Dative Bond & Metallic Bond

33. A single atom shares a pair of electrons, which is also known as
lone pair, to another atom or ion to form a type of covalent
bond. This will lead to the formation of
A Ionic bond
B Dative bond
C Metallic bond
Hydrogen Bond, Dative Bond & Metallic Bond

34. Which of the following compounds has a dative bond?
A Ammonia
B Ammonium ion
C Urea
D Nitrogen
Hydrogen Bond, Dative Bond & Metallic Bond

35. Diagram below shows the formation of hydronium ion, H3O+. Dative bond
was formed by the contribution of
A one electron each from hydrogen atom.
B overlapping of electron between hydrogen atom and oxygen atom.
C the +1 charge from hydrogen ion.
D lone pair from the oxygen atom.
Hydrogen Bond, Dative Bond & Metallic Bond

36. Diagram below shows an arrangement of atoms in solid sodium.
What is X?
A Ion
B Proton
C Electron
D Atom
Hydrogen Bond, Dative Bond & Metallic Bond

37. Which of the following statement is true about metallic bond?
A A force that hold ions together in a solid lattice.
B A force that holds metal atoms together in a solid lattice
C A force that holds molecules together in solid lattice.
D A force that attract any atoms together in solid lattice.
Hydrogen Bond, Dative Bond & Metallic Bond

38. 1. The chemical formula of glucose is C6H12O6. Predict and explain the
solubility of glucose in water.
2. Ammonium ion, NH4+ and hydronium ion, H3O+ are two ions that form
dative bond. Define dative bond.
3. Based on the drawing of Lewis structure, explain the formation of NH4+ .
In your explanation, include chemical equation.
Hydrogen Bond, Dative Bond & Metallic Bond