Where are electrons found in an atom

If the element whose electric configuration ends in the d sublevel, the element is calssified as? a. inner transition b. noble gases c. representative d. transition

What can be added to the examples section of each circle? endothermic: ice melting into water, and a heat pack becoming warm exothermic: a glow stick glowing, and fireworks exploding endothermic: ice melting into water, and an instant ice pack turning cold exothermic: fireworks exploding, and gasoline burning endothermic: a glow stick glowing, and a heat pack becoming warm exothermic: an instant ice pack turning cold, and ice melting into water endothermic: gasoline burning, and an instant ice pack turning cold exothermic: ice melting into water, and an instant ice pack turning cold

What happened in 2012 and how does it illustrate the importance of understanding the sun and how it works?