Bonding And Structure Flashcards
(27 cards)
What is ionic bonding?
Strong electrostatic forces of attraction between oppositely charged ions
Why do ionic compounds have high melting and boiling points?
•Giant Ionic Lattice Structure
•Many strong electrostatic forces of attraction between oppositely charged ions which require lots of energy which require lots of energy to overcome
What is the state of electrical conductivity for ionic compounds?
•Will not conduct electricity in the solid state as ions are in a fixed position
•Will conduct electricity in the molten state as it has mobile ions
What is the state of solubility for ionic compounds?
Ionic Compounds will dissolve in water
What is Covalent Bonding?
A shared pair of electrons between atoms
What is co-ordinate bonding?
•When one atom provides both the electrons needed to form a covalent bond
•The atom donating the electrons must have a lone pair of electrons
•The atom receiving the electrons must have a vacant orbital
What is the name of the molecular shape that has a bond angle of 180. 2 pairs of electrons, with both pairs being bonding pairs?
Linear
What is the name of the molecular shape that has a bond angle of 120, 3 pairs of electrons, with all of them being bonding pairs?
Trigonal Planar
What is the name of the molecular shape that has a bond angle of 109.5, 4 pairs of electrons, with all of them being bonding pairs?
Tetrahedral
What is the name of the molecular shape that has a bond angle of 107, 4 pairs of electrons, with one of those pairs being a lone pair?
Trigonal Pyramid
What is the name of the molecular shape that has a bond angle of 104.5, 4 pairs of electrons with 2 of them being lone pairs?
Non-Linear
What is the name of the molecular shape with a bond angle of 90, 6 pairs of electrons, with all 6 being bonding pairs?
Octahedral
What is electronegativity?
The ability of an atom to attract a pair of electrons in a covalent bond
What is a polar bond?
A covalent bond in which there is an unequal share of the electrons due to the differing electronegativities of the atoms involved
What is the order of increasing IMF strength for similar sized molecules?
London Forces
Permanent Dipole-Dipole
Hydrogen Bonding
What affects the strength of London Forces?
Size/Mr of the molecule
Surface Area contact
What is permanent dipole-dipole forces?
•This type of force occurs between molecules which are polar
•A polar bond is where there is a difference in electronegativity between the atoms
•There is an attraction between the delta plus on one molecule and a delta minus on an adjacent molecule
What is Hydrogen Bonding?
•Only occurs between polar molecules which have a hydrogen directly bonded to oxygen, nitrogen or fluorine
•This leaves the hydrogen nucleus very delta plus
•A lone pair of electrons on a neighbouring molecule containing oxygen, fluorine or nitrogen is then attracted to the hydrogen
Why is ice less dense than liquid water?
•There are fewer particles of water per unit volume in the solid state than the liquid state
•This is because in ice the water molecules are further apart than in liquid water
•This means that there are more spaces between the molecules
Why do simple molecular structures have low melting and boiling points?
Weak IMF between molecules which require very little energy to overcome
What is the state of electrical conductivity for simple molecular structures?
•Will not conduct electricity in the solid state or in the molten state
•There are no charged particles free to move, therefore no mobile ions or delocalised electrons
Why is H2O polar, whereas CO2 is non polar?
CO2 is a symmetrical molecule, so there is no overall dipole
Describe permanent dipole-dipole interactions
Some molecules with polar bonds have permanent dipoles and there are forces of attraction between those dipoles and those of neighbouring molecules
Describe London Forces
•London Forces are caused by random movements of electrons
•This leads to instantaneous dipoles
•Instantaneous Dipole induces a dipole in nearby molecules
•Induced Dipoles attract one another
