The elements of same group are placed in same group as they have similar properties. So Calcium is the element which resembles Mangesium.
Calcium and Magnesium both are alkaline earth metals.
They have similar properties as they have similar outer or valence shell electronic configuration
The general electronic configuration of alkaline earht metal is ns2
The electronic configuration of Mg [atomic number 12] and Ca [atomic number 20] are
![[Ne]3s^{2}](https://tex.z-dn.net/?f=%5BNe%5D3s%5E%7B2%7D)
and ![[Ar]4s^{2}](https://tex.z-dn.net/?f=%5BAr%5D4s%5E%7B2%7D)
respectively.
Mass number is the number of protons and neutrons in an atom, and it tells us about the mass of the atom in amu, or atomic mass units. Atomic mass is the average mass of all the isotopes of a certain type. It is a weighted average that takes into account the abundances of all of the different isotopes
hope this helps :)
To form a salt compound, the acid contribute a NON METAL ION and the base contributes a METAL ION.
In chemistry, acid and base react together to form salt and water only. For the salt formed, the positive metal ion comes from the base while the negative non metal ion comes from the acid.
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