Arrange these elements into the order of the reactivity series:
calcium, copper, iron, magnesium, gold, silver, lead, zinc, sodium, potassium, platinum, aluminium
[blank_start]1[blank_end]
[blank_start]2[blank_end]
[blank_start]3[blank_end]
[blank_start]4[blank_end]
[blank_start]5[blank_end]
[blank_start]6[blank_end]
[blank_start]7[blank_end]
[blank_start]8[blank_end]
[blank_start]9[blank_end]
[blank_start]10[blank_end]
[blank_start]11[blank_end]
[blank_start]12[blank_end]