Por qué dos iones sodio reemplazan un ion de calcio o de magnesio

Why two sodium ions replace a calcium or magnesium ion

Explanation:

Two sodium ions will replace a calcium or magnesium ion because, a sodium ion is has just one positive charge, it has lost an electron. A calcium or magnesium ion has two electrons.

           Sodium ion  -   Na⁺

            Magnesium ion - Mg²⁺      Calcium ion Ca²⁺

For a replacement in the lattice of a mineral to occur between sodium and any of magnesium or calcium, two of it must be used so as to balance the charge properly;

                 Na⁺   +  Na⁺ will replace Mg²⁺ or Ca²⁺ in crystal space

This will allow for perfect charge replacement.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.