Help me please

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope

When casey looks at a cd or dvd she notices that there is a rainbow pattern that is created by the light. she became curious and shone light directly at it and a pattern was created on the wall. what is the cause of this pattern?

An object was measured by a worker as 14.6cm long, however, the manufacturer specifications list the length of the object at 14.4cm. what is the percent error in the worker's measurement?