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Question
Which of this element belong to the period 3? Write their electronic configuration
`3^(Li) , 14^(Si) , 2^(He) , 15^(P)`
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Solution
i. Elements in period 3: `14^S , 15^P`
ii. electronic configuration `14^S : 2,8,4 `
` 15^P : 2 ,8 , 5`
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