How many half-lives does it take a radioactive substance to decay until only 12.5% of the original substance remains?

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.

Stage in which a typical star has completely stopped fusion

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?