Question

where do you expect to find the element with atomic number 20 in the periodic table and why

Answer 1

in group 4 because it has 4 shells... and period
2 coz it has 2 valence electron....

Answer 2

Answer:

Calcium is the element with 'atomic number' 20.  

Explanation:

• Calcium belongs to group 2, period 4, and block ‘s’ in the periodic table.
• This is because calcium is an 'alkaline earth metal' and alkaline earth metals are placed in group 2 in the periodic table.
• These alkaline earth metals like beryllium, magnesium, calcium etc have two valence electrons in their 'outermost shell' with an oxidation state of 2.
• These metals have 'two electrons' to which they lose to form cations. All 'alkaline earth metals' have structural similarity with a full ‘s’ orbital.