paper 1 Flashcards
Radius of nucleus
1 x 10 to the power of -14 m
Radius of atom
1 x 10 to the power of -10 m
How to calculate RAM from isotopes
[(mass no. of isotope 1 × % abundance of isotope 1) + (mass no. of isotope 2 × % abundance of isotope 2)] / 100
What’s an isotope?
An element where the atoms have the same number of protons but a different number of neutrons
What happens when you go down group 0?
The boiling points increase as you go down group 0.
What happens to metals in g1? Why?
As you go down group 1, the metals react more rapidly.
As you go down g1, the radius of the atom increases so there’s a greater distance between the nucleus and the outer electron so the electron is less attracted to the nucleus so its easier to lose.
What happens as you go down g7? Why?
As you go down group 7, the elements get less reactive.
Gains electrons less easily bc there’s a greater distance between the nucleus and outer shell.
Increased distance means attraction between outer electrons and nucleus is lower at the top of g7 which makes it harder for them to attract an electron.
Properties of transition elements
- hard and strong metals
- high melting points
- high density
- much less reactive than g1 metals
- can form ions with different charges
- forms coloured compounds
- can be used as catalysts
Properties of ionic compounds
- form a giant ionic lattice where every positive ion is surrounded by negative ions
- strong electrostatic forces of attraction in the lattice
- very high melting and boiling points
- cannot conduct electricity when solid
Properties of small covalent molecules + why
- low boiling and melting points: weak intermolecular forces which don’t require a lot of energy to break
- intermolecular forces increase as size of covalent molecule increases
- do not conduct electricity: bc they don’t have an overall electric charge
Diamond
- high melting and boiling point
- cannot conduct electricity bc all outer electrons are in covalent bonds so no free electrons to carry charge
- each carbon atom is joined to 4 other carbon atoms
- hard
- uses: cutting tools, oil rig drills
Silicon dioxide
- silicon and oxygen covalently bonded together
- high melting point and boiling point
Graphite
- each carbon atom forms 3 covalent bonds with other carbon atoms
- soft and slippery: hexagonal rings are arranged in layers with no covalent bonds between so they can slide over each other
- good conductor of electricity and heat: has delocalised electrons which can move
- high melting and boiling point
Graphenes
- single layer of graphite so only 1 atom thick
- good conductor of electricity: has delocalised electrons
- strong and has high MP and BP: large number of strong covalent bonds
Fullerene
- hollow shapes
- uses: lubricants in machines, to deliver drugs into the body, catalysts
- carbon nanotubes = fullerenes shaped into long cylinders -> high tensile strength, good conductors of electricity, used to reinforce materials
