Topic 2: Bonding and Structure Flashcards
(32 cards)
When are ions formed?
ions are formed when electrons are transferred from one atom to another
What is an ion?
Charged particle
Define electron transfer
when an electron lost by one atom is gained by another
What is an anion?
Negative ion
What is a cation?
Positive ion
What is electrostatic attraction?
Holds positive and negative ions together - very strong
what is made when oppositely charged ions come together and form and ionic bond?
Ionic compound e.g. Sodium Chloride (NaCl)
What properties would you expect a specific ionic compound to have?
- electrical conductivity - when molten or dissolved (ions in a liquid are free to move and carry a charge)
- Melting point - High melting points due to giant ionic lattices held together by electrostatic forces.
- Solubility - tend to dissolve in water
**Remember
**Even though ionic compounds contain ions they are neutral overall
**when asked to give formula don’t forget charge and formula
What is a giant lattice?
Regular structure that is ‘giant’ because its made up of the same basic unit repeated.
** Different ionic compound have different shaped structure but they are all still GIANT LATTICES.
What is a single covalent bond?
How is a covalent bond formed?
A shared pair of electrons
When 2 atoms share electrons so they both have full outer shells
When are molecules formed?
When 2 atoms (same or different) are joined by a covalent bond - bond is formed by two atoms sharing a pair of electrons.
^^
And there is a strong electrostaticc attraction between nuclei and shared pair of electrons.
How is a covalent bond represented?
by a single line between two symbols (usually both non metals)
When an atom provides both of shared electrons in bonding this is called…
Dative Covalent Bonding
**could be lone pairs
What is metallic bonding?
Positive metal ions are attracted to delocalised negative electrons - they form a giant lattice.
How are metals malleable?
one layer of metal ions is separated from the next by layer of electrons. this means layers can slide over one another with causing metal to break
How are metals conductive?
electricity is a flow of charged particles
in a metal electrons are not attached to any on metal ion and are free to move through the lattice
How do we know metals have high melting/boiling points?
The electrostatic attraction between the positive metal ions and negative electrons make very strong bond.
Bond takes energy to break!
What are bonding pairs and lone pairs?
bonding pairs - shared electrons
lone pairs - unshared electrons
Describe a charge cloud
bonding pairs and lone pairs exist as charge clouds
an area where there is a big chance of finding an electron
What is non-polar covalent bonding?
When electrons are shared equally
What is polar covalent bonding?
When electrons are shared unequally
What is electronegativity?
The ability to attract the bonding pair of electrons in a covalent bond
How is electronegativity measured?
On a Pauling scale
