physical properties

periodic patterns of atomic radii

decreases across a period…the increasingly positive nuclear charge pulls the electrons in the outer shell closer to the nucleus

noble gases

dont have covalent bonds…determined from their Van der Waals forces

Van der Waals radius

measuring the distance between the nuclei of 2 neighboring atoms which are not chemically bonded together then divide by 2…larger than covalent radii due to no electron clouds

across a period

number of electrons and protons increases…shielding effect remains constant as electrons occupy the same principal quantum shell…greater attractive force from increased nuclear charge pulling valence electrons closer to itself

periodic patterns of ionic radius

decreases across a period as the positive charge on the ion increases and the negative charge on the ion decreases…the increasing positive nuclear charge pulls the electrons in the outer shell closer to the nucleus

cation radius

smaller…have lost their outer shell of electrons from their atom…less shielding effect on valence electrons

anion radius

bigger…each atom has gained 1 or more electrons in their valence shell…repulsion forces increase while nuclear charge remains constant

periodic patterns of melting points and electrical conductivity

change in melting point across a period reflects the type of structure and bonding…metals have increasing strong metallic bonds so their melting points increase

why metallic bonding increases melting points

cations are arranged in a giant lattice held together by a sea of deloaclised electrons…delocalised electrons are from the outer most shell…metallic bonds require lots of energy to break

semimetals/metalloids

giant covalent lattties have strong id-id forces…simple molecular lattices have weak id-id forces

periodic patterns of first ionisation energies

general increase in first ionisation energy across a period because the increasing nuclear charge and decreasing atomic radii makes the attractive forces between the nucleus and valence electrons greater