Write the shorthand notation for Cl ^-1 and P ^3-

Question

Please help (:

Answer 1

Your question is not clear, but I think you are asking for the shorthand electron configuration for the chlorine and phosphorous ions.

 

In order to write shorthand electron configurations you need to know how to use the periodic table to write electron configurations.

 

Groups 1 and 2 are the s-block elements, groups 3-12 are the d-block elements, groups 13-18 are the p-block elements. An orbital (any type) can hold up to 2 electrons, so an s-orbital can hold up to 2 electrons, three p-orbitals can hold up to 6 electrons (total), and five d-orbitals can hold up to 10 electrons (total). Counting across the periods (rows) of the periodic table will show the filling order of the orbitals. (1s^# 2s^# 2p^# 3s^# 3p^# 4s^# 3d^# 4p^# ... etc, where # is the number of electrons in that sublevel.

 

A chlorine ion has 18 electrons (17 e- in a chlorine atom + 1 e- to form the chlorine anion having -1 charge). The shorthand electron configuration begins with the symbol of the noble gas having the closest lower atomic number (the noble gas in the row above the element that you are writing the configuration for). The noble gas you would use to write the configuration for the chlorine ion would be neon (Ne) which has an atomic number of 10. This symbol, written inside square brackets [Ne], represents 10 inner core electrons. You follow this with the remaining valence electrons, showing the orbitals in filling order (lowest energy to highest energy).

 

The electron configuration for Cl^-1 is [Ne] 3s² 3p⁶.

 

The phosphorous ion has 18 electrons (15 e- in P atom + 3 e- to form anion P-3)just as the chlorine ion does, so the electron configuration would be the same.

 

Each element in groups 15, 16, and 17 gains the number of electrons needed to have a full valence like the noble gases - because it is most stable with a full valence.