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Question
Right or wrong sentence.
The elements lithium and beryllium are in the same period because their valencies are similar.
Options
Right
Wrong
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Solution
The given sentence is wrong.
Explanation:
- Lithium and beryllium are in the same period because they have the same number of electron shells (they are both in period 2), not because their valencies are similar.
- Valency depends on the number of electrons in the outermost shell; Li has valency 1 while Be has valency 2, so their valencies are different.
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