Which of the following crystals would be softest and most malleable?
co2
c
sio2
mgo

The correct answer is CO2

Explanation:

Carbon dioxide (chemical formula CO 2) has 60% greater density than dry air and is a colorless gas. It is the most soft and malleable crystal from the option given in the question. It exists as a trace gas on earth in nature.

Carbon dioxide is soluble in water and is mostly found in springs and groundwater. One carbon dioxide molecule consists of one carbon atom and two oxygen atoms. Usually when it is in normal concentrations,  it is odorless whereas it has a strong acidic smell under high concentrations.

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.  

the answer is c. nacl