Bonding- the basics

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What is ionic bonding between?

A metal and a non-metal
Do metal ions become positive or negative?

Positive
Do non-metal ions become positive or negative?

Negative
What is the name for a positive ion?

Cation
What is the name for a negative ion?

Anion
Do metal atoms become smaller or larger after ionic bonding? Why?
- Smaller
- Loses electron(s) and becomes cation
- Nucleus same charge
- Electrostatic force to each electron is greater
- Electrons pulled closer so radius is reduced
Do non-metal atoms become smaller or larger after ionic bonding? Why?
- Larger
- Gains electron(s) and becomes anion
- Nucleus same charge
- Electrostatic force to each electron is smaller
- Electrons drift futher so radius is increased
Give the definition for electron affinity.

The energy change when one mole of gaseous atoms acquires one mole of electrons to form one mole of gaseous negative ions (anions).
Give the name of the structure that ionic compounds form.

Giant ionic crystal lattice
Give four properties of ionic compounds.
- Very high melting points
- Strong but brittle
- Only conduct electrivity when aqeous or molten
- Insoluble in non-polar solvents (water is polar)
Do ionic compounds have high or low melting points? Why?
- Very high melting points.
- Because:
- Very strong ionic bonds
- Very strong electrostatic forces
- Forms giant ionic crystal lattice
- Lots of energy needed to separte ions
Are ionic compounds weak or strong? Brittle or malleable? Why?
- Strong and brittle.
- Brittle:
- Dislocate one layer
- Layer moves
- Similar ions become adjacent
- Electromagnetic replusion between similar ions
- Crystal splits
Can ionic compounds conduct electricity?
- Only when aqueous (dissolved) or molten (liquid state).
- Ionis able to move
- So able to carry current
Are ionic compounds soluble? If so in what solvents? Why?
- Only soluble in non-polar solvents (water is polar).
- Lots of energy needed to overcome electrostatic attraction
- Polar molcules surrond ions
- Separate ions
What is metallic bonding between?

Two metals
Draw a metallic compound
Give four properties of metallic compounds.
- Malleable (and ductile)
- High melting point
- Conduct electricity
- Lustre
Are metallic compounds brittle or malleable? Why?
- Malleable.
- Cations in 'sea' of delocalised electrons
- Shift cation layers
- Electrons still there
- Electrostatic forces still there
Do metallic compounds have a high or low melting point? Why?
- High melting point.
- Cations in 'sea' of delocalised electrons
- Strong electrostatic forces
- Lots of energy needed to seperate cations
In metallic compounds, what factors make a difference to the boiling point of the compound? And why?
- Radius of the ions:
- Smaller means cations closer together
- Stronger electrostatic forces
- Number of electrons 'donated' from each atom:
- More means stronger electrostatic force
Do metallic compounds conduct electricity? Why?
- Yes.
- Conduction of electicity needs freedom of movement for charged particles
- Delocatlised electrons can move
What is the name for when a metal shines?

Lustre
Are metallic compounds lustrous? Why?
- Yes.
- Cations in 'sea' of delocalised electrons
- Electrons easily absorb and re-emit photons of visable light
- Smoother the surface=more lustrous
What is covalent bonding between?

Two non-metals
What is a covalent bond?

A shared pair of electrons between two atoms.
What is a intramolecular bond?

A bond between atoms.
What is an intermolecular bond?

A bond between molecules.
How do you show a lone pair of electrons on a stick diagram?

As two dots.
Do covalent compounds have a high or low boiling point? Why?
- Low.
- Strong intramolecular bonds
- Weak intermolecular bonds
- Not much energy needed to seperate molecules for each other
Do covalent compounds conduct electricity? Why?
- No.
- Molecules neutral overall
- No charged particles to carry the current

Author

algebrageek

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Card Set

Bonding- the basics

Description

AQA AS Chemistry

Updated

2012-11-27T21:00:36Z

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