Topic 2 (Types of Bonding) Flashcards
(29 cards)
Define the term ion.
A charged particle by gaining or losing electrons.
What is meant by the term ionic bonds?
The transfer of electrons from a metal atom to another non-metal atom forming positive and negative ions.
What kind of force attracts ionic bonds?
Strong electrostatic forces between the positive and negative ions.
Describe the properties of ionic compounds.
*High melting and boiling points.
*Soluble in water.
*Usually solids.
*They conduct electricity when molten or aqueous.
Why do ionic compounds have high melting and boiling points?
This is because the strong electrostatic forces between the ionic bonds require huge amounts of energy to be broken down.
Why do ionic bonds conduct electricity when molten or aqueous?
This is because the ions are free to carry the charge.
Define the term “Giant Ionic Structure”.
Regular arrangement of alternating oppositely charged positive and negative ions.
State the valency of each compound ion.
Ammonium (NH4): 1+
Hydroxide (OH): 1-
Nitrate (NO3): 1-
Nitrite (N02): 1-
Hydrogen Carbonate (HCO3): 1-
Carbonate (CO3): 2-
Sulfate (SO4): 2-
Sulfite (SO3): 2-
Phosphate (PO4): 3-
Phosphite (PO3): 3-
Define the term Covalent Bonds.
The sharing of electrons between non-metals.
Covalent bonding is for non-metals only since only non-metals need to gain electrons.
Describe the term Molecules.
A group of atoms held together by covalent bonds.
Describe the properties of covalent compounds.
*Low melting and boiling points.
*Do not conduct electricity.
*Mainly gases and liquids but a few are solids.
*Less soluble in water than ionic compounds.
Why do covalent compounds have low melting and boiling points?
This is because the weak intermolecular forces between the molecules need low amounts of energy to be broken down.
Why do covalent compounds not conduct electricity?
This is because there are no free/mobile electrons to carry the electric charge.
Define the term Macromolecules.
Macromolecules are made of billions of atoms bonded together in a covalent structure.
What is meant by the term allotropes?
When the same element exists in several physical forms and structures, it is said to be exhibit allotropy.
Mention two allotropes of carbon.
Diamond and Graphite.
Describe the structure of Graphite.
In graphite, each carbon atom is linked with 3 other carbon atoms by single covalent bonds resulting in the hexagonal ring which is arranged in a layer. The layers of hexagons are bonded by weak forces, so the layers slide over each other.
Describe the properties of Graphite.
*Soft and slippery because the layers of hexagons can slide over each other.
*A good conductor of electricity.
Why does graphite conduct electricity?
This is because each carbon atom has four outer electrons and graphite only bonds to 3, so the fourth electron is free to move and carry the charge.
What are the uses of graphite?
*Electrodes - it can conduct electricity and is unreactive.
*Pencils - it’s slippery and can slide through paper.
*Lubricant - it’s soft.
Describe the structure of Diamond.
Each carbon atom is bonded to four other carbon atoms by strong covalent bonds in a tetrahedral arrangement.
Describe the properties of diamond.
*Very hard because each atom is held by four strong bonds.
*Very high melting point because it needs very big amounts of energy to break the strong bonds.
*Does not conduct electricity because there are no free electrons to carry the charge.
What are the uses of diamond?
*Jewelry - it’s shiny.
*Cutting and drilling - it’s very hard, strong and sharp.
Describe the structure of Silicon dioxide.
Each silicon atom is bonded to 4 oxygen atoms, and each oxygen atom is bonded to 2 silicon atoms.
