Each carbon is bonded to 4 other carbons by strong covalent bonds. There are no free electrons.
Metals are good conductors of electricity and thermal energy because .........
the electrons are free to move and carry an electrical charge
Lattice is ........
a regularly repeating arrangement of ions, atoms, or molecules in 3D
Metals have high melting and boiling points because ........
They are giant structures of atoms with strong metallic bonding
Ionic compound ONLY conduct electricity when melted or dissolved in water because ….......
The ions are free to move and so charge can flow
Mixture of two or more elements, at least one of which is a metal
Alloy
A single sheet of graphite
Graphene
Bonding electron that is no longer associated with any one particular atom
Delocalised Electron
Why are pure metals soft?
Because atoms are arranged in LAYERS which can SLIDE over each other
A giant 3D structure of alternating positive and negative ions, held together by strong electrostatic attraction is called ........
Ionic lattice
Ionic compounds have high melting and boiling points because ..........
They are giant structures of atoms (giant ionic lattice) with strong electrostatic forces of attraction in ALL DIRECTIONS between oppositely charged ions
Polymers are ..........
Polymers are long chain molecules. They are made up of repeating units (monomers) joined together by covalent bonds.
Why carbon dioxide is a gas at room temperature?
Due to their low melting and boiling points
Name three form of the element carbon.
Diamond, graphite, fullerenes
Ionic bonds are formed between a positive metal ion and a negative non-metal is called ........
Giant ionic
Graphite is very hard, has a very high/low melting and boiling point and can/cannot conduct electricity.
high; can
Alloys are harder than pure metals because .........
The layers are DISTORTED (the arrangement of the lattice less regular) so can’t slide over each other
Fullerenes (e.g. carbon nanotubes) are extremely strong and are excellent conductors of thermal energy and electricity because .........
they have strong covalent bonds and free electrons
Why is diamond hard and has very high melting and boiling points?
Each carbon is bonded to 4 other carbons by strong covalent bonds. There are no free electrons
Small molecules have relatively low melting and boiling points because ..........
the intermolecular forces are overcome on melting and boiling and these are weak forces
A form of the element carbon that can exist as cage-like or tubular structures based on hexagonal rings of carbon atoms
Fullerenes
A form of the element carbon where each carbon atom is covalently bonded to 3 others
Graphite
Huge structures made up of atoms (non-metals) joined by covalent bonds is called ..........
Giant covalent
Giant covalent compounds have high melting and boiling points because .........
All of the atoms linked by strong covalent bonds
A form of the element carbon where each carbon atom is covalently bonded to 4 others
Diamond
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