Topic 3 - Chemical Bonding Flashcards
What are ionic compounds?
Oppositely charged ions held together by electrostatic attractions.
Can ionic compounds conduct electricity?
Only in aqueous solution or when molten.
What are the melting points of ionic compounds like?
High.
Why do ionic compounds have high melting points?
Many, strong electrostatic forces between oppositely charged ions that need lots of energy to overcome.
Why do ionic compounds conduct electricity when molten?
The ions are free to move.
Why do ionic compounds conduct electricity when in aqueous solution?
Water molecules are polar and can attract the positive and negative ions and break the structure so the ions are free to move.
Why are ionic compounds brittle?
When struck, the layers slide and positive ions get next to positive ions and repel and break the structure.
What is a way to show evidence for charged particles?
Electrolysis of copper(II)chromate(VI) on wet filter paper.
What color is copper(II)chromate(VI)?
Green.
What happens when a drop of green copper(II)chromate(VI) is placed on wet filter paper and electricity is passed through it?
The ions start to separate.
What is the charge on a copper(II) ion?
2+
Where do the Cu2+ ions go?
They move toward the negative cathode.
What color is the Cu2+ solution?
Blue.
What is the charge on a chromate(VI) ion?
2-
Where do the CrO4^2- ions go?
The move towards the positive anode.
What color is the CrO4^2- solution?
Yellow.
What is covalent bonding?
The sharing of electrons in order for the atoms to obtain a full outer shell.
Where is the electrostatic attraction in a covalent bond?
Between the shared electrons and the positive nucleus.
How many types of covalent bonds are there, and what are they?
3
Single, double, and triple bonds.
What is a dative covalent bond?
Where one atom donates 2 electrons to an atom or ion to form a bond.
What is an alternate name for a dative covalent bond?
Coordinate bond.
How is a coordinate bond represented in a diagram?
An arrow.
What is bond enthalpy?
The strength of the bond.
What is the relationship between bond enthalpy and the length of the bond?
The shorter the bond the higher the bond enthalpy.