Which molecule is most polar?
A) CH3CHO
B)CO2
C)CH3Cl
D)C2H6
E)NONE

the answer is none

Explanation:

Water

Water is the most polar molecule because a bond between oxygen and hydrogen has the most difference out of the atoms listed. Although the oxygen has two hydrogens bonded, this does not decrease the electronegativity of oxygen, but oxygen unfairly shares sets of electrons from both hydrogens, making it more polar still

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.