Answer:
a number assigned to an element in chemical combination which represents the number of electrons lost (or gained, if the number is negative), by an atom of that element in the compound
Explanation:
sodium, magnesium, iron is zero.
Explanation:
As the total concentration is given as 1.2 mM. And, it is also given that salt present in the solution is NaCl.
As sodium chloride is an ionic compound so, when it is added to water then it will dissociate into sodium and chlorine ions as follows.
So, it means in total there will be formation of 2 ions when one molecules of NaCl dissociates.
Therefore, concentration of chlorine ions will be calculated as follows.
Concentration of 
ions = 
= 0.6 mM
Thus, we can conclude that the concentration of chloride ions is 0.6 mM.
Answer: Reactivity is not a physical property, it is a chemical property.
Explanation:
Physical property is a value of matter that can be observed and measured without any change in composition of the matter. Examples of physical properties are color, combustion,melting point,boiling point,solubility, texture, appearance, polarity, odor,viscosity, density and many more.
Chemical properties are characteristics that are obvious or seen when substances undergo chemical reaction. Examples are reactivity,toxicity, acidity, flammability, and heat combustion.
1000 to the power 4 not so good at math but
