<span>Because protons are positively charged and neutrons have no charge then it is safe to say that such an atomic model would have the positive charge concentrated in the center of an atom (option d).</span>
The SI base unit for length is meter.
In order to make smaller measurements, you can use the centi-, milli-, micro-, etc. prefixes.
When you want to reference larger measurements, you can use the kilo-, mega-, giga- and prefixes such as those.
