C3 Flashcards
Alloy
A mixture of two or more elements, at least one of which is a metal
Covalent bond
The bond between two non-metal atoms that share one or more pairs of electrons
Covalent bonding
The attraction between two non-metal atoms that share one or more pairs of electrons
Fullerene
Molecules of carbon that can exist as large cage-like structures, based on hexagonal rings of carbon atoms, carbon molecules shaped like closed tubes/hollow balls
Giant covalent structure
A huge 3D network of covalently bonded atoms
Giant lattice
A huge 3D network of atoms or ions
Intermolecular forces
The attraction between the individual molecules in a covalently bonded substance
Ionic bond
The electrostatic force of attraction between positively and negatively charged ions
Polymer
A substance made from very large molecules made of many repeating units
Ions
Charged particles, as single atoms or broup of atoms
Limitations of dot and cross diagrams
They don’t show:
The structure of the compound
The relative sizes size of the ions/atoms
How ions/atoms are arrangedin space
Ionic lattice
The structure of ionic compounds where there are strong electrostatic forces of attraction between oppositely charged ions, in all directions
Properties of ionic compounds
They have high melting points and boiling points due to the strong bonds between the ions.
When they’re solid, the ions are held in place, so the compounds can’t conduct electricity, but when ionic compounds melts, the ions are free to move and they’ll carry electric charge
Some ionic compounds dissolve in water
Why are covalent bonds strong?
The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces, making covalent bonds very strong
Advantages of displayed formulas
Good at showing how atoms are connected in large molecules
Disadvantages of displayed formula
Don’t show the 3D structure of the molecule
Don’t show the atoms the electrons in the covalent bond have come from
Advantages of 3D models
Show atoms, covalent bonds and arrangement in space next to each other
Disadvantages of 3D models
Confusing for large molecules where there are lots of atoms to include - don’t show where the electrons in the bond have come from, either
Advantages of dot and cross diagrams
Show the arrangement of electrons in an atom/ion, show which atom the electrons in an ion originally come from
Examples of simple molecular substances
Hydrogen
Chlorine
Oxygen
Nitrogen
Methane
Water
Hydrogen chloride