Section Two (Structure and properties) Flashcards
What is a simple covalent molecule?
Small molecules with covalent bonds between the atoms.
Do simple covalent molecules have low or high melting and boiling points?
Low.
Do simple covalent molecules have strong or weak inter-molecular bonds?
Weak (this is why they have low boiling/melting points).
Do simple covalent molecules conduct electricity?
No, the molecules do not have an overall charge.
What are simple covalent molecules between?
Non-metals.
What structure do ionic compounds have?
Regular structures (giant ionic lattices) in which there ate strong electrostatic forces in all directions between the oppositely charged ions.
Do ionic structures have low or high melting & boiling points?
High (very strong bonds means a lot of energy needed to break them).
Do solid ionic structures conduct electricity?
No, they have to be melted or dissolved in water so the ions are free to move.
What is a giant covalent structure?
Large structures joined by covalent bonds.
Give three examples of a giant covalent structure.
Diamond, graphite & silicon dioxide.
Do giant covalent bonds have low or high melting & boiling points?
High as covalent bonds are strong.
Why are diamonds very hard?
Each carbon atom forms four covalent bonds with the other carbon atoms.
Why is graphite soft and slippery?
Each carbon atom bonds to three others forming layers; the layers are free to slide over each other because there are no covalent bonds between the layers.
Why does graphite conduct heat and electricity?
One electron from each atom is delocalised, causing there to be a charge.
Why do metals conduct heat and electricity?
There is a sea of delocalised electrons between the metal atoms.
