The electronic arrangement of an atom shows how electrons are distributed across the different energy levels. Which of the following elements is represented by the electron arrangement 2, 8, 18, 6? А Сa
B. Mg
C. S
D Se
E. Ga

The biomedical technique in which a part of the brain is destroyed with electric current is known as a. electroconvulsive therapy b. prefrontal lobotomy c. bilateral cingulotomy d. tardive dyskinesia

4al + 3o2 → 2al2o3 what does the "3" in front of o2 stand for? a) it indicates that there are 5 oxygen atoms after you add the coefficient and the subscript. b) it indicates that that there are are total of 6 oxygen atoms all bonded together as a single molecule. c) it indicates that there are 3 oxygen molecules chemically bonded to each other in the reaction. d) it indicates that there are 3 separate oxygen molecules in the reaction.

372 ml is the volume of aluminum, density is 2.70 g/ml what is the mass in grams