periodic table
key patterns in the periodic table
-group number is the same as the number of outer shell electrons -the atoms of group viii have a full outer shell of electrons so they are unreactive -the period number is the same as the number of electrons shells
what are alkali metals
soft silvery and have 1 outer shell electron
properties of alkali metals
-softer than most metals -lower density than most metals -lighter than most metal -low melting points
how do alkali metals react with water
react vigoriously with water forming hydroxide solutions as hydrogen bubbles off
how do alkali metals react with chlorine
burst into flames
how do alkali metals react with oxygen
burn fiercly to form flames
why are alkali metals so reactive
-form ions with +1 charge they have the most drive to lose electrons as they only need to lose one
what are halogens
different colours -all poisionous -form diatomic molecules
trends in physical properties of halogens
density increase = boiling point increase
trends in chemical properties of halogens
reactivity decreases as you go down group vii
key trends on the periodic table
-atoms achieve a full outer shell by taking part in reactions -the number of electrons in the outer shell affects reactivity -the number of outer shells affects reactivity -density increases down all groups
describe the change of metal to non-metal in the periodic table
there is not a clear line between metals and non-metals on the periodic table there are metalloids which share metal and non-metal properties
physical properites of transition elements
-high density -high melting point -hard and strong -good conductors of heat and electricity
chemical properties of transition elements
- less reactive than froup ome metals -so not show trends in reactivity -most are coloured compounds -many act as catalysts - many form ions with different charges -form more than one compound with other elements