Bonding Flashcards
How are covalent bonds formed?
A shared pair of electrons between two non-metal elements
How are ionic bonds formed?
By the transfer of electrons between a metal and a non-metal element
An ion is a
Charged particle
Metals lose electrons to form
Positive ions
Non-metals gain electrons to form
Negative ions
What are the properties of covalent molecular bonds?
Low melting and boiling points because of the weak bonds between the molecules
Insoluble in water
Do not conduct in any state
What are the properties of covalent network substances?
Strong bonds
Solids at room temperature
Extremely high melting and boiling points
Do not conduct in any state
Name 3 of the 5 substances that have a covalent network Structure
2 compounds - silicon dioxide (Sand), silicon carbide
3 elements - carbon (diamond), carbon (graphite) and boron
How are the charged particles in metals arranged?
A giant lattice of positively charged metal ions in a sea of delocalised electrons.
What is a metallic bond?
A metallic bond is the electrostatic attraction of the positive ions and the delocalised electrons
Why can metals conduct electricity in any state?
Metals can conduct because of the flow of delocalised electrons
What is the only liquid metal?
Mercury (Hg, 80)
What is the structure of an ionic compound?
Ionic substances are arranged in an ionic crystal lattice
- positive ions are surrounded by negative ions and the negative ions are surrounded by positive ions, they are held together by the electrostatic attraction between the charges
What are the properties of an ionic compound?
High melting and boiling points
Conducts as a solution or molten
Soluble in water
Why do ionic compounds conduct as solution/molten and not as a solid?
When ionic substances are solid the ions are trapped in the ionic crystal lattice and therefore there is no flow of charged, whereas when they are in a liquid state the ions are free to move.
The colour of an ionic compound comes from
The coloured ions present
When an ionic compound is melted or dissolved in water, what is formed?
An electrolyte is formed.
An electrical insulator is
A material that can’t conduct electricity
What is electrolysis?
Electrolysis is the breaking down of an ionic compound using electricity
How are atoms in covalent bonds held together?
By the electrostatic attraction of the positively charged nuclei and the negatively charged electrons
Why do covalent substances not conduct?
There is no flow of charges
A molecule is an atom
Held together by covalent bonds
Why are graphite electrodes used during electrolysis?
Because the graphite rods conduct electricity and are unreactive
Why do metals form at the negative electrode during electrolysis?
Metals have positive ions which attract to the negative charge of the electrode
Why do non-metals form at the positive electrode during electrolysis?
Non-metals have negative ions which attract to the positive charge of the electrode
How do you work out the state of a substance at a particular temperature?
The melting and boiling points are found on page 5 (elements) and page 9 (compounds) in the data book
If the melting point is higher than the temperature given the substance is a solid. If it is lower the melting point it is a liquid.
If the boiling point is lower than the temperature given but the temperature given is above the melting point it is a liquid. If it is higher it’s a gas.
What are the four steps of a reaction mass calculation?
- Write out balanced equation
- Identify the substances you’ll use in the calculation
- Write the mol statement
- Calculation
What are the four types of bonding?
- Metallic
- Ionic
- Covalent network
- Covalent molecular
