Atomic Structure - Covalent Flashcards
What is a macromolecule?
A giant covalent structure
What 3 things so substances consisting of simple molecules have?
Low melting and boiling points. Weak intermolecular forces. Do not conduct electricity.
Why do simple molecular substances have low melting and boiling points?
Because the molecules are easily parted from each other. Intermolecular forces get broken.
Why don’t molecular substances conduct electricity?
There’s no ions so there’s no electrical charge.
What are 3 examples of giant covalent structures (lattices) of atoms?
Diamond and graphite (forms of carbon) and silicon dioxide (silica).
Why do the atoms in giant covalent structures have high melting/boiling points?
They are linked to other atoms by strong covalent bonds.
Why is diamond hard?
Each carbon atom forms 4 covalent bonds with other carbon atoms in a giant covalent structure.
Why is graphite soft and slippery?
Each carbon atom bonds to three others, forming layers. Layers slide over each other because there are no covalent bonds between the layers.
In graphite, how many electrons from each carbon atom are delocalised? What does this allow?
One. These delocalised electrons allow graphite to conduct heat and electricity.
What can carbon also form? Use?
Fullerenes. Used for drug delivery into the body, lubricants and catalysts.
How are covalent bonds formed?
When atoms share pairs of electrons
