Bonding Flashcards
What does ionic bonding occur between?
metals and non metals
How are electrons transferred in an ionic bond?
Metal atoms to non metal atoms
How are the ions attracted by in ionic bonds?
Oppositely charged ions are attracted by electrostatic force of attraction
What do ionic compounds always exist as?
A lattice
What is the melting and boiling point of Ionic compounds?
-Solid at room temp (not enough energy to overcome strong electrostatic forces of attraction)
-High melting points as they are giant structures
How does charge affect melting point in ionic compounds?
Melting points are higher for lattices containing ions with greater ionic charges , as there is stronger attraction between ions. Ionic attraction also depends on the size of the ions.
If a atom is larger then will it have stronger intermolecular forces? Why?
Yes it does as the electrons further away from the nucleus have larger forces of attraction due to the distance between the nuclues.
In what state do ionic compounds conduct electricity?
Conduct electricity in molten or aqueous but not in a solid
Why do ionic compounds not conduct electricity when in a solid?
-in a solid the ions are in a fixed position
-so ions cant move and therefore cannot conduct electricity
Why can ionic compounds conduct electricity when aqueous or molten (liquid)?
-Solid ionic lattice breaks down
-ions are now free to move
-so electricity is conducted
Whats the bond between atoms with a covalent bond?
Electrostatic force of attraction between the nuclei and shared electrons
What is a covalent bond?
When two atoms share one or more pair of electrons
What are the special elements we have to watch out for?
-Boron
-Phosphorus
-Sulfur
2 examples of special cases?
-Boron trifluoride BF3 (boron only has 6 electrons in outer shells)
-Sulfur hexafluoride SF6 (sulfur has 12 electrons in outer shell)
How do the strength of covalent bonds differ?
-how much the outer atomic orbitals of the bonded atoms overlap
-how strongly the atomic nuclei are attracted to the shared electrons.
How do you find out the strength of a covalent bond?
Look at its average bond enthalpy
What does average bond enthalpy measure?
the energy required to break a covalent bond
Properties of covalent bonds:
-atoms within a molecule are strongly bonded with covalent bonds
-There are weak intermolecular forces betweem the molecules
-Dont need much energy and low melting point
-poor conductors of electricity because there are no charged particles to carry current
What is co-ordinate/dative bonding?
When one atom provides both the electrons in a covalent bond
How are co-ordinate bonds represented?
The arrow points towards the atom that is accepting the electron pair
Why are some atoms more electronegative than the other?
electrons in a covalent are not always evenly shared as these electrons may experience more attraction
from one of the bonded atoms than the other
What factors affect electronegativity?
-Nuclear charge
-Atomic radius
-Shielding
How does shielding affect electronegativity?
Smaller number of shells 🡪 less repulsion from inner shell electrons 🡪 greater attraction towards shared
electrons 🡪 greater electronegativity
