What element has the noble-gas notation [Ne]3s23p5?

The element that has the noble gas configuration ##"[Ne]3s"^(2)"3p"^5"## is chlorine. One way you can determine this is to count the total number of electrons, which in a neutral atom will be the same as the number of protons, which is the atomic number of the element. Then you can look up the element with that atomic number on the periodic table .

##"[Ne]"## in the electron configuration means that the element has the electron configuration of neon, plus the two 3s electons and the five 3p electrons. The atomic number of neon is 10, which means it has 10 protons and 10 electrons. So add the 10 electrons from neon to the 7 electrons from the 3s and 3p sublevels, and you get 17 electrons. In a neutral atom, this would also be its atomic number. The element with the atomic number 17 is chlorine.