Which period is Ca (20) in?

1 Answer
anor277
Aug 8, 2018

Surely there must be a Periodic Table in front of you if you are doing your chemistry homework?

Explanation:

The one in front of me now tells me that calcium, #Z=20#, belongs in the FOURTH Period, the fourth row on the Periodic Table....and thus its valence electrons are #4s#. The electronic configuration of the metal is...

#1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^2#

...the electronic configuration of the common ion, #Ca^(2+)# is thus...

#{1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)}^(2+)#

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