Covalent Bonding Flashcards
(22 cards)
Types of bonds broken- N2->N2
Dispersion forces
Types of bonds broken-hg->hg
Metallic bonds
Types of bonds broken- 2NaCl-> 2NA+CL2
Ionic bonds
Hydrogen bonding
Can only occur with oxygen,florine and Nitrogen
A typical feature of covalent molecular substances
They are gases, liquids or soft, low melting point solids at room temperature
Type of Bond must be broken for water to vaporise
Hydrogen bonds only
Difference between ionic and molecular substances
Do not conduct In the molten state, whereas ionic substances do
Why do H:Y:H and .. not have the same shape H :Z:H ..
Because Element Y has 2 lone pairs which are not included in the lewis diagram whereas Z has no lone pairs. Y would perfrom a Linear shape where Z is a tetrhdyral shape because Y is a group 16 atom and Z is a group 14 atom
Ethanol (CH3Ch2Oh) has a
A High melting point
Graphite is
Brittle
Methane (Ch4) does not
Conduct electricity in the solid or aqueous state
Polar Molecule
When a stronger attraction comes from the element with a higher electronegativity. Must have different electronegatvity and or an incomplete turnaround
Non Polar Molecule
Molecular elements are always non polar because they have the same electronegativty
Why are Molecular compounds sometimes polar and non polar?
It depends on their electronegativity. It also depends on the shape of the molecule as well on bond dipoles. If the bond dipoles cancel out then it will be non polar
The intramolecular and intermolecular forces in water
Dipole dipole, hydrogen bonding and dispersion forces
Why is the density of ice less than the density of water
Because the regular arrangments of the water molecules in ice take up more space than the irregular arrangment of molecules in liquid
What is a Covalent bond?
A bond that exists with only non metals. Neighbouring atoms share electrons to achieve a full outer shell. Atoms try to achieve a stable noble gas config of 8 outer shell electrons
What are the physical properties associated with covalent bonding?
Do not conduct electricity because the molecules are electrically neutral, Vary in their solubility (Polar compounds are soluble in polar solvents such as water but in soluble in non polar solvents), Have low boiling and melting points since the forces between them are weak.
The trend in physical properties based in the intermolecular forces in operation?
?
What type of bonding occurs between water in its different states?
Hydrogen bonding, Di-dipole bonds and dispersion forces
Water in liquid
Water molecules move too quickly in liquid form to form regular structures however they still remain attacthed.
Water being frozen
Water molecules expand when frozen. Water molecules join together to form hexagonal structures
