Bonding Flashcards
Compound ion formula for a: Nitrate; Carbonate; Sulfate and Ammonium.
NO3- ; CO3 2- ; SO4 2- and NH4 +.
How are ions formed?
When electrons are transferred from one atom to another.
What is an ionic bond?
An ionic bond is electrostatic attraction between two oppositely charged ions.
What is an ionic crystal?
It is a giant lattice of ions.
What is a giant lattice?
A regular structure that has the same basic unit repeated over and over again.
Do ionic compounds have electrical conductivity?
When they are molten or dissolved in water they can as their free ions can carry the electrical charge. However, when solid they cannot as the strong ionic bonds hold the ions in place.
Explain the trends of melting and boiling points in ionic compounds.
They have generally high melting and boiling points as the electrostatic force require a lot of energy to overcome.
Why are ionic compounds usually double in water?
Water is a polar molecule, part of it has a slight mega tie charge and part of it has a slight positive charge. The water molecules pull the ions away from the lattice causing it to dissolve.
What bond are molecules help together by?
They are held together by strong covalent bonds.
When do double or triple bonds form?
When an atom are sharing more that one pair of electrons.
What is dative covalent bonding?
It is when an atom provides both of the shared electrons.
How is can dative bonding be shown in a stick diagram?
By using an arrow.
Why aren’t covalent compounds electrically conductive?
They have no free ions or electrons to carry the charge.
Why do covalent compounds have low boiling and melting points?
This is due to weak forces between the molecules even though they have strong attraction within molecules.
Can covalent compounds dissolve in water?
Some do, it depends on their polarity.
Why is graphite used as weak lubricant or in pencils?
Weak bonds between the layers are easily broken.
Why can graphite conduct electricity?
Delocalised electrons move in between the sheets.
Why is graphite used to make strong, light weight sports equipment?
The layers are far apart giving it a low density.
Why does graphite have a high melting and boiling point?
The strong covalent bonds between the hexagon sheets.
Is graphite soluble?
No as the covalent bonds between the sheets are too hard to break.
What properties do diamonds have due to their strong covalent bonds?
High melting point
Very hard
Good thermal conductor as vibrations travel easily
Cannot conduct electricity - all atoms held in localised bonds.
Doesn’t dissolve in any solvents
Describe the structure of a diamond.
In a giant covalent bond, each carbon atom is covalently bonded to four other carbon atoms. Atoms arrange themselves in a tetrahedral shape.
Describe the structure of graphite.
Arranged in sheets of flat hexagons covalent bonded with three carbon atoms. Fourth outer electron is delocalised. Sheets of hexagon bonded together by van der waals
Describe the structure of giant metallic lattice.
Outermost shell is delocalised leaving positive metal ions. These ions are attracted to the delocalised electrons. Lattice is closely packed together in a sea of delocalised electrons.
