Antoine Lavoisier
How is chemical bond formed?
Chemical bond formed from the transfer and sharing of electrons.
State one example of ionic compound and its uses in daily life.
1. Sodium chloride, NaCl in table salt.
2. Ammonium nitrate, NH4NO3 in fertilizers.
3. Sodium bicarbonate, NaHCO3 in antacid to relieve gastric pain.
Covalent bond is formed from the _______________ of electrons between _______________ atoms and ___________ atoms.
Covalent bond is formed from the sharing of electrons between non-metal atoms and non-metal atoms.
State one similarity of ionic bond and covalent bond.
1. Involves valence electrons.
2. Atoms form ionic bond and covalent bond to achieve a stable duplet or octet electron arrangement.
Ionic compound have __________ melting point and boiling point.
Covalent compound have __________ melting point and boiling point.
Ionic compound have high melting and boiling point.
Covalent compound have low melting point and boiling point.
How many chemical bonds have we learned? What are they?
5. Ionic bond, covalent bond, hydrogen bond, dative bond, and metallic bond.
Hydrogen bond exists in _____________ molecules.
Water molecules, H2O
Ammonia molecules, NH3
Hydrogen fluoride molecules, HF
What are the three types covalent bond?
Single covalent bond, Double covalent bond and Triple covalent bond.
Is methanol, CH3OH is soluble in water?
Explain your answer.
Yes, methanol, CH3OH is soluble in water.
Methanol, CH3OH is able to form hydrogen bond with water molecules, H2O.
Ionic compound can conduct electricity in _________________________________.
Ionic compound can conduct electricity in aqueous solution or molten state.
Ammonium ion, NH4+
Hydroxonium ion, H3O+
Define metallic bond.
Metallic bond is the strong electrostatic force between the negatively-charged sea of electrons and positive metal ion.
Define dative bond.
Dative bond is a covalent bond where the electron pair shared comes from one atom only.
Define free pairs/lone pairs.
Free pairs/lone pairs refers to a pair of electrons that are not shared with another atom in a covalent bond.
Also known as unshared pairs or non-bonding pair, free pairs can be found in the outermost shell of atoms.
Covalent compound usually dissolve in ______________ but do not dissolve in ______________.
Covalent compound usually dissolve in organic solvent but do not dissolve in water.
Why does a wet finger help to turn the pages of a book?
The water molecules, H2O on the fingers will form hydrogen bonds with the cellulose in paper.
Cellulose consists of hydrogen atoms, H that are bonded to oxygen atoms, O.
Because of the that, the paper stick to the finger.
Define hydrogen bond.
Hydrogen bond is the electrostatic attraction force that exists when hydrogen atom is bonded to an electronegative atom such as nitrogen, oxygen and fluoride (N, O, F).
Give 1 example of molecules that form :
1. Single covalent bond
2. Double covalent bond
3. Triple covalent bond
1. Single covalent bond : Chlorine molecules
2. Double covalent bond : Oxygen molecules
3. Triple covalent bond : Nitrogen molecules
In metal lattice structure, the valence electrons from the metallic atoms are free to move throughout the metal structure.
These mobile electrons are also know as
In metal lattice structure, the valence electrons from the metallic atoms are free to move throughout the metal structure.
These mobile electrons are also know as delocalized electrons.
Why does ionic compound cannot conduct electricity in solid form?
The ions in solid ionic compound cannot move freely because they are tied by strong electrostatic attraction force. There ionic compound cannot conduct electricity.
Explain briefly the formation of potassium ion, K+.
Potassium atom has an electron arrangement of 2.8.8.1.
Potassium atom has 1 valence electron.
Potassium atom releases 1 electron to achieve a stable octet electron arrangement to form potassium ion, K+ with electron arrangement of 2.8.8.
Why does water, H2O have a higher boiling point that nitrogen, N2?
Water molecules have hydrogen bond and Van der Waals attraction forces.
More heat is required to break the hydrogen bond and overcome the Van der Waals attraction forces. Hence, boiling point of water, H2O is higher.
Nitrogen, N2 do not form hydrogen bond have lower boiling point compared to water, H2O.
Formation of covalent bond can be visualized using Lewis structure. Lewis structure only shows ______________________________.
the valence electrons of the atoms involved
Water molecules help overcome the electrostatic attraction force between ions and break down lattice structure of the solid ionic compound.
Thus, the ions can move freely in water.
Metals can conduct electricity because ...
Metals can conduct electricity because the electrons in the sea of electrons are free electrons which are able to carry charges.