Bonding Flashcards
What is electronegativity?
The power of an atom to attract the pair of electrons in a covalent bond.
Why does electronegativity decrease down a group?
Further from nucleus, harder for nucleus to attract another electron.
Why does electronegativity increase across a period?
More protons decrease the atomic radius making it easier to gain an electron.
What is a polar bond?
A covalent bond in which electrons are shared unequally (difference in electronegativity).
What is ionic bonding?
Strong electrostatic forces of attraction between oppositely charged ions held in a lattice.
What are the melting and boiling points of ionic compounds like?
Ionic compounds have high melting points and boiling points because of their giant ionic lattice and the strong attraction between bonds.
Do ionic bonds conduct electricity?
Not in a solid state because ions are not free to move. In liquid or solution they can because ions are free to move.
What increases the strength of ionic bonding?
Greater charge and smaller ionic radius.
What is metallic bonding?
Strong electrostatic attraction between cations and the sea of delocalised electrons.
How many cations should you draw in an exam for metallic bonding diagrams?
At least 6 and have delocalised electrons proportional to that.
What affects the strength of a metallic bond?
Ionic charge (higher=stronger), number of delocalised electrons (more=stronger), ionic radius (smaller=stronger).
What are the melting and boiling points of metals like?
High because of the giant metallic lattice and the strong attraction between cations and delocalised electrons.
Do metals conduct electricity?
Yes, the free electrons are able to carry a charge.
Why are metals malleable?
The layers of atoms in a metal can slide over each other and the attraction between electrons and cations keeps the compound together.
What is a covalent bond?
Sharing of electrons between atoms.
What does expanding the octet mean?
Having more than 8 electrons in their outer shell.
What is needed for a co-ordinate bond to occur?
Atom donating must have a lone pair, atom receiving must have a free orbital.
What is a co-ordinate bond represented by?
An arrow.
How do you find a molecule’s number of lone pairs?
Identify the group number of the central atom which shows how many outer electrons it has. If it’s an ion add or subtract the charge. Count the number of single bonds formed by the central atom and add this to the total from step 2. Divide this by two which shows how many electron pairs there are. Minus the number of bonds from this number. That will show the lone pairs.
What is the electron pair repulsion theory?
LP-LP>BP-LP>BP-BP. Molecules will form the shape that has the least repulsion.
What do angles decrease by for each LP?
2.5°.
What are the three types of intermolecular forces?
Van der Waals Forces, Dipole-dipole forces and hydrogen bonding.
Where do intermolecular forces exist?
Simple molecular bonds only.
How do you determine whether a bond is polar or non-polar?
If it has no difference in electronegativity or is symmetrical it is non-polar.