In solid NaCl, each sodium ion is surrounded. by six chlorine ions and each chlorine ions is surrounded by six sodium ions. This arrangement results in a... A) malleable noncrystalline structure
B) ductile, malleable solid with mobile electrons
C) weak crystalline solid that conducts electricity
D) high melting point and crystalline structure

the answer would be D

Explanation:

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.