C13 Structure And Bonding Flashcards
Particles in a solid
No gaps, tightly packed
Cannot be compressed
Vibrate about a fixed point
Regular arrangement
Particles all the same size
Strong forces holding them together
Particles in a liquid
Particles are free to move - weak forces hold them together
Tightly packed, all touching and no spaces
No overlapping
Random arrangement
Cannot be compressed
Particles in a gas
Spread out (none touching)
Particles all the same size
No overlapping
Random arrangement
Most energy required to break bonds
Specific latent heat
Energy used to break bonds
Steps in latent heat of fusion
- Energy increases vibration of particles
- Energy used to break bonds between solid particles.
- Energy increases kinetic energy of liquid particles. Temperature increases, particles are faster. (LIQUID)
- Energy used to overcome forces of attraction between particles.
- Energy used increases random rapid movement of particles. (GAS)
What is ionic bonding?
Oppositely charged ions are bonded between non-metals and metals.
What is covalent bonding?
Atoms which share pairs of electrons. Mostly between non-metallic elements.
What is metallic bonding?
Atoms which share delocalised electrons - in metallic elements and alloys.
What are ions?
Atoms have a neutral charge because they always have an equal number of protons and electrons. If they gain/lose electrons, they become charge and are called ions.
Positive and negative ions stick together as opposite charges attract.
Atoms want to gain/lose electrons to achieve a full outer shell.
Metal atoms lose electrons- positive ions
Non-metal atoms gain electrons - negative ions.
What is a period on the periodic table?
The number of electron shells of that element.
What is a group on the periodic table?
Number of electrons in outer shell
Maximum number of electrons in each shell?
2,8,8
What is the overall charge of an ionic compound?
Balanced
EXAMPLE QUESTION: Magnesium and dilute hydrochloride acid react to produce magnesium chloride solution and hydrogen. Explain why magnesium chloride has a formula MgCl2 and not MgCl
Because you need two chlorine atoms to bind to one magnesium atom to balance the overall charges.
Properties of giant ionic structures
Ionic substances form giant lattices
Many strong electrostatic forces between the ions
Regular arrangement means they form crystals
Solid ionic substances do not conduct electricity as the ions are not free to move throughout the substance
High melting point
All solid at room temperature because the melting point is above room temp
Higher BP
Molten ionic substances can conduct electricity because molten ions are now free to move
Dissolved ionic substances can conduct electricity because dissolved ions are free to move