The modern model of the atom describes electrons in a little less specific detail than earlier models did. Why is it that being less sure about the placement of electrons in an atom is actually an improvement over earlier models? Electrons do not follow specific paths, so describing the area where an electron is likely to be is more scientifically accurate.
Electrons were thought to be negatively charged, but now scientists know that their charge depends on their energy level.
The modern model is based on mathematical equations, so the results become less clear when the decimals are rounded.
The position of electrons in atomic models has changed so much that it is better to have a less specific model than to be wrong again..

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).

d eras and periods

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.