Bonding And Structure Flashcards
(37 cards)
Why are ionic compounds hard?
Strong electrostatic attraction between the cations and anions which hold the ions in fixed positions
What is the definition of ionic bonding?
An ionic bond is the strong electrostatic attraction between anions and cations
Why do ionic compounds not conduct electricity when solid?
The ions are fixed in a giant lattice. They cannot move and carry charge
What are ionic compounds?
Ionic compounds are giant structures with strong electrostatic attraction between cations and anions which are held in place in a fixed structure by these forces
Why do ionic compounds conduct electricity when molten or in solution?
The ionic bonds are broken and the ions are free to move and carry charge
What is the definition of covalent bonding?
The strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms
Why do ionic compound solids have high melting and boiling points?
Strong electrostatic attraction between cations and anions which needs a lot of energy to overcome
Why does non polar simple covalent not dissolve in water?
Water is polar. There is no attraction between polar water molecules and non polar molecules
Why does polar simple covalent dissolve in water?
The delta H+ water is attracted to the delta - of polar molecule and visa versa
Why do covalent compounds not conduct electricity?
No electrons or ions that are free to move
Why do ionic compounds dissolve in water?
Water is polar the slightly positive part of a water molecule attracts anions and the slightly negative part attracts cations
Why do simple covalent molecules have a low mp and Bp?
The intermolecular forces between molecules are weak and not much energy is needed to overcome them
What is dative covalent bonding?
A special form of covalent bonding where both electrons come from only one atom and none come from the other
How do you predict the shape of a molecule?
Total number of pairs on central atom
How many bonding
How many lone
What is the bond angle and shape of SF6?
90 degrees octahedral
Why are giant covalent solids with a very high mp?
There are many strong covalent bonds throughout the 3D lattice which require a lot of energy to break
How much does a lone pair reduce bond angle by?
2.5 degrees
What is the bond angle and shape of NH3?
107 degrees pyramidal
Why are metallic bonded items strong?
Strong electrostatic attraction between delocalised electrons and positive ions holds the ions in a fixed positions in the lattice
What is the bond angle and shape of Bf3?
120 degrees and triginal planar
Name three giant covalent structures
Silicon dioxide diamond graphite
What is a permanent dipole dipole?
Polar molecules will attract each other
What is the bond angle and shape of BeCl2v?
180 degrees linear
What is the definition of electronegativity?
The ability of an atom to attract the bonding pair electrons in a covalent bond
