6. Neon has 10 electrons - 2 in the inner shell and 8 in the outer shell. This arrangement of 8 electrons in the outer shell is extremely stable and makes neon inert, with a valence of zero. Sodium has 11 electrons - 2
in the first shell, 8 in the next shell, and I in the outer shell. Fluorine has 9 electrons - 2 in the first shell
and 7 in the outer shell. How could sodium and fluorine from a compound in which both elements would
be like neon with 8 electrons in the outer shell?

Let look at EC of Sodium(Na)

Now look at EC of Fluorine

Now the Compound will be

3 1/4 %

explanation:

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.