Bonding - Structure and Bonding Flashcards
What is ionic bonding?
Ionic bonding is the electrostatic force of attraction between a positively charged ion (metal) and a negatively charged ion (non-metal) and they transfer electrons.
What is covalent bonding?
When atoms share electrons (non-metal and non-metal)
What is metallic bonding?
With 2 positive ions (2 metals) and alloys. The electrostatic attraction between a lattice of positive ions surrounded by a sea of delocalised electrons. The sharing of delocalised electrons results in strong metallic bonding .
Name the properties of ionic compounds
- High melting and boiling points
- Can’t conduct electricity as a solid - they can when they are a liquid as ions are free to move
- Solid at room temperature
Why do small covalent have low melting and boiling points (they are usually gases at room temperature)?
The intermolecular forces are weak, therefore it requires very little energy
Name 2 properties of small covalent molecules
- They can’t conduct electricity
- They have low melting and boiling points
Name 2 properties of large covelent molecules
Such as diamond and graphite
- Higher melting and bioling points as they have many bonds
- Most can’t conduct electricity but some do
Why are covalent bonds strong?
Covalent bonds are strong because the shared electrons are attracted to the nucleus of both atoms
Metallic Bonding
What are delocalised electrons?
Electrons that are free to move
Why are metals good conductors?
They have delocalised electrons which can move, the electrons can move which can carry an electric current/ thermal energy (heat) through the whole structure
Why are metals malleable?
Delocalised electrons allow metal atoms to slide past one another without being subjected by strong repulsive forces that could cause materials to shatter.
What are alloys?
A mixture of 2 or more different elements (one has to be a metal)
What is an example of an alloy?
Steel - it’s mostly iron but 2% of carbon
Name the properties of metals
- Shiny
- Malleable
- Ductile
- High melting/boiling points
- Conductors of electricity and heat
True or False: Metallic bonds are weaker than ionic and covalent bonds.
True
What are cations?
Positive ions
Describe the structure of metals
They have a regular,lattice,compact structure,giant structure,delocalised electrons and have cations
What happens when cations slide over each other?
A dent is formed
Why aren’t ionic substances malleable?
The like poles would cause repulsion and therefore make the whole thing shatter.
What are anions?
Negative ions
What are allotropes?
Different structural forms of the same elements and can have different physical properties and chemical behaviours.
What is an example of an allotrope (carbon)?
Graphite, Charcoal and diamond
Why do ionic substances have high melting and boiling points?
Because they have many bonds and the forces between the bonds are really strong, therefore they require lots of energy to break
What group is not involves in ionic bonding?
Group 0, Noble Gases
What does the mass number (top) mean?
Number of protons + number of neutrons (protons and neutrons in the nucleus)
What does the atomic number (bottom) mean?
Amount of protons or electrons
Why do ionic substances have high melting points?
Ionic substances have so many bonds and the forces in the bonds are really strong. Therefore, it requires lots of energy to break these bonds.
What are ions?
Ions are atoms that have gained or lost electrons, therefore they have a charge
Why can’t covalent compounds conduct electricity?
They don’t have any charged particles to conduct
Why are ionic substances a solid at room temperature?
- Electrostatic attraction/ionic bonds are strong
- The electrostatic attraction comes from all directions between oppositely charged ions
- Forming a giant lattice
- Large amount of energy to needed to break the strong bonds
- Therefore it has a high melting point
Why does chlorine, a small covalent molecule, a gas at room temperature?
- The covalent bonds between atoms
- Forming simple molecules
- Weak attraction between molecules
- Therefore, a low boiling point
What charge is an ion when it loses an electron?
Positive
What charge is an ion when it gains an electron?
Negative
What do metals rely on to keep the metal together?
Electrostatic force of attraction
