What type of reaction is displayed below?
HCI + NAOH → NaCl + H20​

neutralization reaction

Explanation:

This reaction involve an acid (HCl) reacting with a base (NaOH), producing a salt (NaCl) and water. Therefore it's a neutralization reaction

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

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.