Explain, in terms of atomic structure, why barium has a lower first ionization energy than magnesium.

Factor out the greatest common factor. minus − 14 14p3 plus + 10 10p2 plus + 4 4p

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.

Aplan that covers all qualified higer education expenses is known as a