Answer:
nobmelonisegxfixcyctGkchkcigdtidtifyoc
D. Two electrons in its first energy level; eight electrons in its second energy level; six valence electrons in its outermost energy level.
Please correct me if I'm wrong!! :)
Ten name if this compound is Potassium Oxide
After 3 half life periods you would have 5 grams of krypton left because half of 40 is 20 half of 20 is 10 and half of 10 is 5