What characteristic shared between chlorine, fluorine, and bromine makes them have similar properties?

a. all have seven valence electrons.
b. all have the same number of protons in their outermost energy levels.
c. all have two electrons in their first energy levels.
d. all have a similar state of matter.

The Correct Answer is A. If you look at the periodic table of elements, you may notice that Chlorine (Cl, #17), Fluorine (F, #9), and Bromine (Br, #35) are all in the same family (or column). That is group VIIA or 17. VII is 7 in roman numerals and that is the number of valence electrons.

Hope that helps!

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.