When ionic compounds are added to water, they dissociate or break apart into ions. In the case of table salt, salt added to water dissociates into sodium ions and chloride ions. This would seem to be a chemical change. However, scientists do not consider this to be one, because the solid table salt remains after the water is evaporated. The atoms recombine into their original arrangement once the water is removed. Which word from the selection helps you understand that physical changes can be undone? a added b dissociate c recombine. d removed

b dissociate

Explanation:

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.  

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).