4NA - The Periodic Table Flashcards
what is the significance of the period number
the number of electron shells
[*common mistake - it is wrong to say the number of valence shells]
what is the significance of the Group number
the number of valence electrons
why do elements in the same Group have similar chemical properties
same number of valence electrons
elements in the Periodic Table are arranged according to their mass number. true/false
false. elements are arranged according to their atomic/proton number
elements across a period change from metallic to non-metallic character. true/false
true
[metallic character: lose electrons
non-metallic character: gain electrons]
state one physical property of Group I elements that is different from other metals
soft / low density / low melting point
state the trend in reactivity of Group I elements down the Group
reactivity increases down the Group
give the general chemical equation for the reaction of Group I metals in water
2 M ((s) + 2 H2O (l) –> 2 MOH (aq) + H2 (g)
what colour will Universal indicator give if it is added to a mixture of Group I metals and water
purple
[alkaline solution is formed when Group I metals are added to water]
why are all the halogens found in Group VII
their atoms all have seven valence electrons each
[reject: same number of valence electrons]
state the chemical formula of the halogens
fluorine - F2
chlorine - Cl2
bromine - Br2
iodine - I2
[halogens exist as diatomic molecules]
state the physical state of the halogens at room temperature
fluorine - gas
chlorine - gas
bromine - liquid
iodine - solid
state the colour of the halogens at room temperature
fluorine - pale yellow
chlorine - pale green-yellow
bromine - reddish-brown
iodine - black
state the trend in reactivity of Group VII elements down the Group
reactivity decreases down the Group
what is a displacement reaction
a more reactive halogen will displace a less reactive halogen from its compound
