Answer:
Ca:
Explanation:
A Lewis structure shows the number of valence electrons about an atom.
Ca is in Group 2 of Period 4.
Its electron configuration is [Ar]4s².
Thus, Ca has two valence electrons and its Lewis structure is Ca:
Because the solid is soluble in water, it cannot be calcium fluoride.
This leaves us with either silver fluoride or potassium bromide, as both are soluble in water.
Upon addition of sodium sulfate, a white precipitate forms, confirming that the substance was silver fluoride as the precipitate are of silver sulfate.
Answer: E. 78%
Explanation:
Diborane (B2H6), a chemical compound made up of approximately 78% Boron and 22% Hydrogen.
Explanation: Skeletal muscle, attached to bones, is responsible for skeletal movements. The peripheral portion of the central nervous system (CNS) controls the skeletal muscles. Thus, these muscles are under conscious, or voluntary, control. The basic unit is the muscle fiber with many nuclei. These muscle fibers are striated (having transverse streaks) and each acts independently of neighboring muscle fibers.
