Question

3Li,11Na,20Ca,4Be,9F
1.which of this elements belong to the period 3
2.which of this elements have valence 1
3.which of this elements belong to group 2

Answer 1

1. Na

2. Li and Na

3.Li ,Be and F

Answer 2

Answer:

1. Na

2.Na,Li,F

3. Be,Ca

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