bonding- ionic+covalent+metallic Flashcards
what is ionic bonding?
strong electrostatic forces of attraction between oppositely charged ions held in a lattice.
eg of an ionically bonded substance
NaCl
How high are ionically bonded subtsances’ bp and melting point? why?
High - takes a lot of energy to break strong electrostatic forces of attraction between oppositely charged ions.
Do ionic compounds conduct electricity?
Yes, when molten/in solution ad the ions are free to move and carry charge. They do not conduct electricity in solid.
Do ionic compounds dissolve in water?
yes they do. water molecules are polar so part of the molecules have partially positive and partially negative charge . these charged parts pull ions away from the lattice, causing it to dissolve.
what is covalent bonding?
when molecules form by sharing electrons - there is an electrostatic attraction between the nuclei and the shared electrons.
how many electrons are shared in a double covalent bond?
4
What is dative covalent bonding?
where one atom provides both electrons. they are represented by arrows.
What is metallic bonding?
lattice of positive metal ions strongly attracted to a sea of delocalised electrons.Layers can slide over eachother- malleable
does metallic compounds have high or low MP or BP?
Yes because there is a strong electrostatic force of attraction between the positive ions and negatively charged sea of delocalised electrons.
does metallic compounds conduct electricity?
Yes as the delocalised electrons can move throughout the metal to carry charge.
How does the strength of metallic bonds change across the periodic table?
—> increases
there is higher charge on metals so more delocalised electrons per ion…leading to a stronger electrostatic force of attraction between them.
what is simple molecular covalent bonding?
strong covalent bonds between the atoms, weak van der waals forces between the molecules.
Are there any lone pair of electrons in simple covalent bonds?
No - all electrons are involved in bonding
can simple molecular covalent molecules conduct electricity? why?
No - all electrons are involved in bonding and arent free to move.
do simple molecular substances have high or low mtp or bp? why?
Low- there are weak van der waals forces of attraction between the molecules which dont take much energy to overcome.
describe macromolecular covalent bonding?
lattice of many atoms held together by covalent bonds.
do substances with macromolecular covalent bonds have high mp or bp? why?
high, as it takes a lot of energy to overcome many covalent bonds.
describe the structure of a diamond?
tetrahedral, each carbon atom bonded to 4 other carbon atoms
describe the structure of graphite?
- macromolecular covalent
-each carbon atom is bonded to 3 other so it is in layers - weak VDW forces between layers so layers can slide over each other.
- one electron from each carbon is delocalised so can conduct electrcity.
