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? a. electrons do not follow specific paths, so describing the area where an electron is likely to be is more scientifically accurate. b. electrons were thought to be negatively charged, but now scientists know that their charge depends on their energy level. c. the modern model is based on mathematical equations, so the results become less clear when the decimals are rounded. d. 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.

A.Electrons do not follow specific paths, so describing the area where an electron is likely to be is more scientifically accurate.

Explanation:

Earlier electrons were thought to be revolving around the nucleus of the respective atom in circular paths. But later on it was established that they do not follow specific paths. In fact, electrons can never be located at a particular position around nucleus so we can only define an area where probability of finding an electron is more. These areas are known as orbitals like s orbital, p orbital, d orbital and f orbital.  

According to Heisenberg's uncertainty principle, it is impossible to find the exact location of an electron around the nucleus that is why we can only talk about orbitals where probability of finding an electron is more than any other region.

The expression for Heisenberg's uncertainty principle is as under:

                                Δx . Δp  ~ h / 2 π

        where, Δx = uncertainty in position

                    Δp = uncertainty in momentum

                      h = Plank's constant

According to Heisenberg's uncertainty principle, if we will try to find out the location of electron it's velocity will change and if we will try to find out its velocity then its position will change so it is impossible to find its exact location.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.