The half-life of carbon-14 is approximately 5700 years. An archaeologist unearths a piece of wood that is determined to have 83% of its carbon-14 remaining. Using carbon-12 dating techniques, approximately how old is the ancient
piece of wood that she located?
A)
approximately 675 years old
B)
approximately 1,550 years old
approximately 3,700 years old
D)
approximately one million years old

100 points answer quick the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?

4. a 20-kg child is tossed up into the air by her parent. the child is 2 meters off the ground traveling 5 m/s. circle one: ke / gpe / both show your work for finding the values of each type of energy the object has: