The number of radioactive nuclei in a particular sample decreases to one-eighth of its original number in 9 days. What is the half-life of these nuclei

Classify each statement about effective nuclear charge, zeff, as true or false.

There is an area in idaho named craters of the moon where most of the ground is covered with basalt, adark gray, igneous rock with no visibl crystals. what can you infer about the geographical history of the area?

You may expect bonds between two atoms which each have n covalent lonic metallic hydrogen