Covalent Bonding

Questão	Responda
Non-metal atoms need to ....(gain/lose) electrons in order to get a stable electronic structure.	Gain
In covalent bonding, atoms...(take, share) electrons	Share electrons
A covalent bond is...	When a shared pair of electrons attracts the two atoms forming a bond.
Covalently bonded substances form...	Molecules
When drawing covalent bonds, you only draw...	The outer energy level of the atoms
Carbon forms several bonds which join to give giant covalent structures called...	Macromolecules
What are the forces called that hold the atoms/ions together?	Electrostatic forces of attraction
Which direction do these forces of attraction act in?	All directions
Do ionic compounds have a high or low melting/boiling point? Why?	High Because the intermolecular forces are very strong. A lot of energy is needed to break them
Do covalently-bonded molecules have a high or low melting/boiling point? Why?	Low Because their intermolecular forces are very weak but the covalent bonds are very strong. Very little energy is needed to overcome them
Does a simple molecule conduct electricity when a liquid?	No There is NO overall charge in simple molecules.
Why are larger molecules more likely to be a liquid at room temperature rather than a gas?	Because larger molecules have stronger forces of attraction which are harder to break. They would not be a solid because they do not have as strong bonds as ionic compounds.
Give an example of an atom which forms a giant covalent structure...	Carbon
There are no.... in giant covalent structures	Intermolecular forces Every atom is joined by covalent bonds
Diamond has a three dimensional structure of carbon atoms. Each atom is bonded to ... other atoms.	Four
Graphite is another form of carbon. Each atom is bonded to ... other atoms.	Three
Why is graphite so slippery and grey?	Because it is made up of giant, flat two dimensional layers. There are no intermolecular forces between the layers so they can easily slide over each other
In graphite, each carbon atom has one delocalised electron. What does that mean?	It means that a bonding electron is no longer associated with a particular atom.
Why does graphite conduct electricity and heat?	Because it has delocalised electrons like the electrons in a metal.
What are fullerenes?	Fullerenes are molecules that make hexagonal rings of carbon atoms that form cage-like structures when joined together.
Some fullerenes are...	Nano-sized
What are some known uses of fullerenes?	Catalysts, lubricants, drug delivery and reinforcing materials.
What is a catalyst?	A substance that speeds up a chemical reaction. Afterwards, the catalyst is chemically changed.
Giant Covalent Structures are...	Insoluble in water

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	Criado por Charnanigan14 quase 11 anos atrás