The table below gives the numbers of protons, electrons, and neutrons in four atoms. AtomNumber of protonsNumber of neutronsNumber of electrons 1989 2998 39910 49109 Based on the table, which atom has a charge of –1? 1 2 3 4

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.

there are two significant figures.