Question

(1) Predict the number of valence electron
(2)What is the number of shells in Sr?
(3)Arrange Be,Ca,Mg and Rb in the increasing order of size of their respective atoms.
(4)Predict whether Ca is a metal of non metal
(5)Which one of these elements has the largest atomic size?

Answer 1

1. Rb ( 2.8.8.8.8.3) , valence electron is 3

2. Sr(2.8.8.8.8.4), valence is 4

3. Be, mg , ca, rb

4. Ca is a metal as it belongs to group 2 in the mordern periodic table

5.rb

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Answer 2

Answer:

1)Rb valence electrons is 1 since it is in group 1

2)5 as the period number is equal to the number of shells

3)Be,Ca,Mg,Rb

4)Ca is a metal since it loses it 2 valence electrons and forms a positive ion

5)Rb has the largest atomic size

Explanation: