Which of the following group 7a elements is the most reactive?
a. cl (chlorine)
b. i (iodine)
c. f (fluorine)
d. br (bromine)

D.na is the answer hope this

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom