<span>A. insoluble solids in water
</span><span>C. solids of different sizes</span>
Answer:
Estos elementos se denominan metales de transición, metales pesados, elementos del bloque D, etc.
Explanation:
Aquí, en esta pregunta, queremos saber la razón por la cual hay un espacio de 10 elementos entre el calcio, que es un elemento del grupo dos, y el galio, que es un elemento del grupo 3.
Al observar la tabla periódica, la tabla periódica moderna, notamos un bloque de elementos entre los elementos del grupo 2 y los elementos del grupo 3 en la tabla periódica.
Entonces, ¿por qué se colocan estos elementos entre ambos grupos? Se colocan aquí porque no pertenecen en su totalidad al grupo 2, ni tampoco al grupo 3.
Estos elementos presentan una especie de estados de oxidación variables que son responsables de una amplia variedad de propiedades comunes entre ellos.

. Iron is divalent to hydrogen and water.
From the ideal gas equation,

where n is number of moles, R is Universal gas constant, P is pressure, V is volume, and T is temperature of the gas.
The pressure and volume are inversely proportional to each other at constant temperature and number of moles.
Hence, on decreasing the pressure, the volume will increase.
As the hiker reaches a height of a mountain, the pressure would decrease which results in the reestablishment of equilibrium between gas molecules thus resulting in pushing of bag outwards.
Hence, the bag will expand as the hiker reaches the top of the mountain.
Answer:
A mixture is a physical combination of substances thus it only requires physical processes to separate. However, a compound is chemically combined and can only be separated by chemical processes. Therefore, it is much harder to separate a compound than a mixture.