Multiple Choice
Which element is considered the most reactive metal among the alkali metals in the periodic table?
2. Atoms & Elements
Periodic Table: Group Names
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To which group of the periodic table does an element with the electron configuration 1s2 2s2 2p1 belong?
A
Group 14 (Carbon group)
B
Group 2 (Alkaline earth metals)
C
Group 1 (Alkali metals)
D
Group 13 (Boron group)
Verified step by step guidance1
Identify the element's highest energy level and the type of orbital where the last electron is added. The given electron configuration is $1s^2\ 2s^2\ 2p^1$, so the highest energy level is $n=2$ and the last electron enters a $p$ orbital.
Determine the total number of valence electrons by counting electrons in the outermost shell (here, the $2s^2$ and $2p^1$ electrons). This gives a total of 3 valence electrons.
Recall that the group number for main-group elements can be related to the number of valence electrons. Elements with 3 valence electrons belong to Group 13 (Boron group).
Match the valence electron count to the periodic table group: since the element has 3 valence electrons, it belongs to Group 13, which includes boron and its congeners.
Confirm that the element is not in Group 1 (1 valence electron), Group 2 (2 valence electrons), or Group 14 (4 valence electrons), thus verifying that Group 13 is the correct group.
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