Bonding Flashcards
What is a covalent bond?
Sharing a pair of electrons between two atoms
What is electronegativity?
The power of an atom to attract the pair of electrons in a covalent bond
How does electronegativity increase throughout the periodic table?
It increases as you go to the right kf the period table
Also increases as you go up the table
What causes a polar bond?
When the more electronegative element in a covalent bond pulls the share of electrons closer to itself
What causes a non polar bond?
when two atoms in the bond are the same
they have an equal share of electrons
e.g. F2
What is ionic bonding?
strong electrostatic force of attraction between oppositely charged ions
NOT A BOND BUT AN ATTRACTION
What is the structure of an ionic bond?
giant ionic lattice
What are some properties of ionic compounds?
- solid at room temp due to giant lattice
- high melting/boiling point due to strong electrostatic attraction
- don’t conduct electricity as solid bc ions arent free to move
- brittle
What is metallic bonding?
strong electrostatic force of attraction between positive metal ions and the sea of delocalised electrons
What factors effect the strength of a metallic bond?
- ionic charge (high=strong)
- atomic radius (small=stronger)
- number of delocalised electrons (more=stronger
What are some properties of metals?
- good conductors as delocalised electrons are free to move
- high melting/boiling point due to strong attraction between positive ions and delocalised electrons
- malleable as layers of ions slide over each other
What is Co-ordinate bonding?
When one atom provides both electrons needed to form a covalent bond
LP-LP > BP- LP > BP-BP
idk just remember that
What are properties of a symmetrical (non polar) molecule?
- bonded to the same atoms
- NO lone pairs
What is a dipole?
occurs when there is an uneven distribution of electron density in a molecule
What is a Van der Waals force?
a temporary dipole in one molecule induces a dipole in another
there is an attraction between δ+molecule and δ-
What affects the strength of VDW forces?
Size/Mr of molecule (bigger=more forces)
Surface area contact (more SA = more forces)
What is a permanent dipole dipole force?
occurs between polar molecules
the δ+ on one molecule attracts the δ- on a neighbouring molecule
What is hydrogen bonding?
occurs between polar molecules which have a hydrogen directly bonded to oxygen nitrogen or fluorine
these are the most electronegative atoms, pulling pair if electrons closer to themselves leaving hydrogen very δ+
What are some features of a Hydrogen bonding diagram?
- partial charges on ALL atoms
- all lone lairs shld be clearly shown
- hydrogen bond shown between lone pair and δ+ on other molecule
Why is ice less dense than liquid water? (hydrogen bonding)
there’s fewer particles of water per unit of volume in the a solid state
in ice water molecules are further apart than in liquid
so theres more gaps between molecules
Can a giant ionic lattice conduct electricity?
when molten or dissolved
this is because ions are free to move
but not when theyre solid
What is the melting/boiling point of a giant ionic lattice?
HIGH
due to strong electrostatic attraction between opposite ions
Dies a giant metallic lattice conduct electricity?
yes
delocalised electrons are free to move
