I have the same question right now and i think that it is D
Answer:
If the electronegativity difference is greater than 2.0, then the bond is ionic.
Explanation:
For ex:
Na has the electronegativity of 0.93
Cl has the electronegativity of 3.16
we subtract 3.16-0.93
We have 2.23 electronegativity difference between Na and Cl
because 2.23 > 2.0
therefore NaCl compound has an ionic bond.
A chemical bond that involves the transfer of electrons from a metal to a nonmetal and thus forms ions and the atoms in the molecule are attracted towards each other through electrostatic force of attraction are said be ionic bond. In short, the bond formed between the two oppositely charged ions.
In salt, the compound formed between sodium and chlorine is sodium chloride having molecular formula 
where sodium is a metal and chlorine is the non-metal. The formation of the compound takes place by transfer of an electron from sodium thus forming a cation of formula 
to chlorine which gains electron and thus results in an anion formation having formula 
. The force of attraction between these oppositely charged ions that helds them together and results in formation of compound is electrostatic force of attraction.
Hence in salt, the nature of bond between sodium and chlorine is ionic.
<span>All acids form their conjugate base and a proton or H+ in an aqueous solution, in water. Since formic acid is an acid, although a weak electrolyte, it will react with water to form the conjugate base HCOO with a negative 1 charge. The other solute will be the proton H+, also written as hydronium H3O+.</span>
The answer is carbon, silicone, germanium
