Na-23 has 11 protons. how many neutrons does it have

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the independent variable in galileo's experiment? a. the speed of the ball b. the slope of the plane c. whether the ball moved d. what the ball was made of

If one fission reaction of a uranium-235 atom produced two neutrons, how many neutrons would be released if the chain reaction occurred three more times?

Quickly what are the following of organisms that existed over a wide area but only for a limited time period called a.soft fossils b.mold fossils c.index fossils d.trace fossils