Answer : The correct symbol and charge for each of the ions must be and .
Explanation :
Covalent compound : It is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound.
The covalent compound are usually formed when two non-metals react.
Ionic compound : It is defined as the compound which is formed when electron gets transferred from one atom to another atom.
Ionic compound are usually formed when a metal reacts with a non-metal.
As we know that the sodium chloride is an ionic compound in which sodium is an alkali metal and has one valence electron and chlorine is a non-metal and has 7 valence electrons.
When sodium atom donates an electron to a chlorine atom then it forms an ionic compound that is sodium chloride (NaCl) and the resulting positive ion and negative ion form a stable ionic compound.
Hence, the correct symbol and charge for each of the ions must be and .
The velocity of any gas particles is inversely proportional to the molecular mass of the the gases. Lighter gases posses higher kinetic energy than heavier gases. From the list given, Neon is the lightest of the four gases with an atomic mass of 4.03 thus it is the lightest. Velocity contributes to the Kinetic energy of the particle. Thus A) Neon is the correct answer.