2. Structure And Bonding Flashcards
(50 cards)
What are the three different types of bonding in compounds?
Ionic, covalent and metallic
Between which particles does ionic bonding occur?
Between a metal and a non-metal, e.g. sodium chloride
Between which particles does covalent bonding occur?
Between 2 non-metal atoms which share pairs of electrons
Between which particles does metallic bonding occur?
Between metal atoms and in alloys
How is a metallic bond formed?
By the attraction between positively charged metal ions and the sea of delocalised electrons that are free to move throughout the structure
How does ionic bonding work?
Positive and negative ions are formed when a metal reacts with a non-metal and transfers electrons, the oppositely charged ions are strongly attracted to each other, forming ionic bonds
How are ionic compounds arranged?
In giant ionic lattices
How can ionic bonding be shown as a diagram?
Using a dot and cross diagram
What are the forces between ions called?
Electrostatic forces
How do the forces between ions act and what does this mean?
The electrostatic forces act in all directions and are very strong meaning the ions are held together very tightly
Why do ionic compounds have high melting and boiling points?
There are many strong ionic bonds to break which requires a lot of energy as to separate the ions you have to overcome the electrostatic forces of attraction acting in all directions and
What are the advantages and disadvantages of using 3D models to represent ionic compounds?
2D & 3D Space filling models? BBC Bitesize
Advantages:
Provides a clear and spatial representation of ions, easier to understand
Disadvantages:
Can be complex, doesn’t show electron transfer, doesn’t show how the next layer of ions is arranged
BBC Bitesize - 3D space-filling model shows lots of free space between ions which there isn’t
What are the advantages and disadvantages of using the ball and stick model to represent ionic compounds?
Advantages:
Shows the arrangement of ions in a larger section of the crystal
Disadvantages:
Does not accurately show the distances between ions which leads to misinterpretations of the relative sizes of ions, using sticks for bonds is misleading as the forces of attraction acting in all directions
Can ionic compounds conduct electricity?
If it is a liquid or has dissolved in water to form an aqueous solution
How does metallic bonding work?
The electrons from the outer shells of metal atoms are delocalised and free to move throughout the structure, and the sharing of these delocalised electrons results in strong metallic bonding
- The metallic bond is the attraction between the positive metal particles and negative delocalised electrons
Why can metals conduct electricity?
Their delocalised electrons carry charge throughout the metal
Why are metals good conductors of thermal energy?
Their delocalised electrons transfer energy
Why do metals have high melting and boiling points?
The metallic bonding in the giant structure of a metals is very strong and large amounts of energy is needed to overcome the metallic bonds
Why are metals malleable and ductile?
In pure metals, the atoms are arranged in neat layers, so when a force is applied the layers if metal atoms can slide over each other
Why are alloys harder than pure metals?
They are harder than pure metals as there are different sizes of atoms and the bigger atoms disrupt the layers of a pure metal, meaning more energy needs to be applied for the layers to slide over each other
What is covalent bonding?
When non-metal atoms share pairs of electrons
What are the forces between molecules in covalent structures?
Weak intermolecular forces
How strong are covalent bonds?
Strong
What are the different types of covalent bonds?
Single covalent bonds where the bond contains one pair of electrons
Double covalent bonds where the bond contains two pairs of electrons and so on
