A. They are in the same period
B. Their salts are colourless
C. They have the same number of valence electrons
D. They are very reactive
Correct Answer: Option C
C. They have the same number of valence electrons
A. They are in the same period
B. Their salts are colourless
C. They have the same number of valence electrons
D. They are very reactive
Correct Answer: Option C
C. They have the same number of valence electrons
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