Periodicity

repeating trends of physical or chemical properties

it increases- the number of shells increases and so does shielding and the outermost electron gets further from the nucleus meaning theres weaker attraction between the nucleus and outer electron

It decreases- the number of protons increases and shielding stays the same so theres stronger attraction of the nucleus and outer electron

the energy required to remove 1mol of electrons from 1 mol of gaseous atoms

X(g) —–> X+(g) + e-

down a group ionisation energy decreases, the electron is removed from a higher principal energy level meaning it is further away from the nucleus and there is more shielding and hence there is weaker attraction between the nucleus and the outer electron so less energy is required to remove the electron

across a period ionisation energy increases because although shielding stays constant the number of protons increases and hence the atomic radius decreases meaning there is stronger attraction between the nucleus and outer electron which will require more energy to remove

although ionisation energy increases across a period, it will decrease when going from group 2 to 3 because the electron is removed from a higher energy p sub-level so theres weaker attraction between the nucleus and outer electron which will require less energy to overcome

although ionisation energy increases across a period, it will decrease when going from group 5 to 6 it will decrease because there is a pair of electron in the p orbital meaning there is extra repulsion and less energy is required to remove the electron

it will always increase as the atomic radius decreases, the nuclear attraction on the outer electron increases so more energy is required to remove an electron from a positive ion

when you see a large jump in ionisation energy an electron is removed from a shell that is much closer to the nucleus so if theres a big jump between ionisation energy 3 and 4 the element must be in group 3

strong electrostatic attraction between positive ions and delocalised electrons

-the ionic charge on the metal (higher=stronger bond) -the number of delocalised electrons (more=stronger bonds) -the ionic radius (smaller=stronger bonds)

-metals are good conductors of heat and electricity as they have delocalised electrons which are free to move and flow -very high melting and boiling points as they have strong electrostatic attractions between positive ions and delocalised electrons -malleable and ductile as there are layers of ions that can slide over eachother

-each carbon atom is bonded to 4 other carbon atoms and the structure has strong covalent bonds which require lots of energy to break -doesn’t conduct electricity (no delocalised electrons) -high melting and boiling points (strong covalent bonds which require lots of energy to break)

-each carbon atom is bonded to 3 other carbon atoms forming hexagonal layers they have strong covalent bonds which require lots of energy to break and weak london forces between the layers -yes, delocalised electrons are free to move and flow -high ( strong covalent bonds which require lots of energy to break)

-1 layer of graphite, each carbon atom is bonded to 3 other carbon atoms forming a hexagonal layer, strong covalent bonds which require lots of energy to break -yes delocalised electrons are free to move and flow -high (strong covalent bonds which require lots of energy to break)

-each silicon atom is bonded to 4 other silicon atoms, (strong covalent bonds which require lots of energy to break) -no (no delocalised electrons) - High (strong covalent bonds which require lots of energy to break)

-each Si atom is bonded to 4 oxygen atoms, strong covalent bonds which require lots of energy to break -no, no delocalised electrons

elements: bonding: structure: Na,Mg,Al Metallic giant metallic lattice Si Covalent giant covalent P,S,Cl Covalent simple molecular Ar mono- simple molecular atomic

element: bonding: structure: Li,Be metallic giant metallic lattice B (not covered in spec) C covalent giant covalent N,O,F covalent simple molecular Ne mono- simple molecular atomic

very high MP and BP due to strong covalent bonds which require a lot of energy to break

high MP and BP due to strong electrostatic attraction between positive ions and delocalised electrons

low MP and BP as they have weak intermolecular forces between the molecules which require less energy to break