Here's why:

* Valence electrons are the electrons in the outermost shell of an atom, which are involved in chemical bonding.

* The electron configuration Ne3s²3p⁵ tells us:

* Ne represents the electron configuration of neon, which has a full outer shell (2s²2p⁶)

* 3s² means there are 2 electrons in the 3s subshell.

* 3p⁵ means there are 5 electrons in the 3p subshell.

Since the 3s and 3p subshells are the outermost shells, the total number of valence electrons is 2 + 5 = 7.