Where do you find a valence electron?

Will mark brainliest how many electrons can be held in the energy level n = 4?

The graph shows one consequence of urban sprawl. how did urban sprawl contribute to the change in biodiversity

What sources of error may have contributed to the percent yield not being 100 percent? think about things that may have led to inaccurate measurements or where mass of the product could have been lost if this experiment was conducted in a physical laboratory.