The lines in an element's atomic spectrum result from electron spins going in opposite directions.

energy that is spread out among an atom's electrons.

electrons moving from a lower to a higher energy level.

electrons moving from a higher to a lower energy level.

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

Working with si (metric) units for each of the following commonly used measurements, indicate its symbol. liter gram milliliter kilogram meter centigram milligram centimeter kilometer second millimeter milliseconds

How many joules of heat are required to raise thetemperature of 750 g of water from 11.0 °c to 19.0 °c?