B----------- oxide is the correct answer
Answer:
As you move across a period, the atomic mass increases because the atomic number also increases. ... The atomic mass for any given atom mainly comes from the mass of the protons and neutrons.
Explanation:
Answer:
Atomic neutron mass electron number
Explanation:
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
and
respectively.