What is the correct distribution of electrons in the electron shell of a helium atom?

4. absorption has the highest risk of overdose due to increased potency. a. rectal b. oral c. transdermal d. intranasal

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy

How do you know when a chemical reaction has occurred