Topic 3- Bonding Flashcards
What are the 3 main types of intramolecular bonds?
Metallic
Ionic
Covalent
What elements are unable to form intramolecular bonds?
Noble gases
What is the structure of a metallic bond?
Giant metallic lattice of positive ions in a sea of delocalised outer electrons
What is a metallic bond?
Electrostatic attraction between the positive ions and delocalised outer electrons
What elements are metallic bonds found in?
Liquid and solid metals
What are the strength of metallic bonds?
Varies but are mostly strong
What is the trend in metallic bonds as you go down a period?
They get weaker as the de localised outer electrons are further from the nuclear charge and are less strongly
What are intramolecular bonds?
Bonds formed between atoms to get a full outer shell
Why can metallic bonds conduct electricity?
delocalised electrons are free to move
What is the structure of an ionic bond?
ionic crystal lattice of + and - ions
What is an ionic bond?
is the electrostatic attraction between + and - ions
What are ionic bonds found in?
compounds containing a metal, ammonium and a non metal
What are the strength of ionic bonds?
v.strong, high mpt and bpt.
What does ionic bonds conduct in?
when molten or in solution, ions are free to move
How are ions formed?
outer electrons from the metal are completely transferred to the non metal.
What are the structure of covalent (network) bonds?
a giant lattice of covalently bonded atoms/
Name four covalent network substances?
Diamond, graphite, silicon dioxide and silicon carbide
What is structure of covalent (discrete) bonds?
discrete molecules held together by weak intermolecular.
What is a covalent bond the result of?
The covalent bond is a result of two positive nuclei being held together by their common attraction for the shared pair of electrons.
Why do ionic bonds exist?
because the difference in electronegativities is great enough for bonding electrons to be transferred completely from the metal to the non-metal atom.
What is the relationship between ionic character and difference in electronegativity of the elements?
the greater the diff in the electronegativity value of the elements in a bond, the more ionic character it has.
What are pure covalent bonds?
The electronegativities of both atoms are identical and the bonding electrons are shared equally between both atoms e.g. H2, S8.
What are polar covalent bonds?
Polar covalent bonds are formed when the attraction of the atoms for the pair of bonding electrons is different. Delta positive (δ+) and delta negative (δ-) notation can be,used to indicate the partial charges on atoms, which
give rise to a dipole (eg H δ+̶ Clδ-).
What is the electronegativity difference in polar bonds?
usually a difference of at least 0.5
