MediumChemistryHigh School (9–10)GeneralThe Periodic Table › Development of the Periodic TableNumerical

The periods of the modern table hold 2, 8, 8, 18, 18, 32 and 32 elements.

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The periods of the modern table hold $2$ , $8$ , $8$ , $18$ , $18$ , $32$ and $32$ elements. What is the atomic number of the last element of period $6$ ? Which group is it in, and which family?

Need a reminder? The key ideaShow

The modern table is ordered by atomic number: $18$ groups and $7$ periods holding $2$ , $8$ , $8$ , $18$ , $18$ , $32$ and $32$ elements. The period is the number of shells. Groups 1 and 2: group $=$ outer electrons. Groups 13 to 18: group $= 10 +$ outer electrons.

The worked solution

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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.

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The periods of the modern table hold 2, 8, 8, 18, 18, 32 and 32 elements.

The worked solution

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