Provide the electron configurations (spdf notation, orbital diagram, and noble-gas-core abbreviation) for Phosphorus (P) and Chlorine (Cl).

Here are the electron configurations for each species, presented in spdf notation, orbital diagram, and noble-gas-core abbreviation.

• a) Phosphorus (P) Phosphorus has an atomic number of 15, meaning it has 15 electrons.

  • spdf notation: $$1s^2 2s^2 2p^6 3s^2 3p^3$$
  • Orbital diagram: $$1s: \underline{\uparrow\downarrow} \quad 2s: \underline{\uparrow\downarrow} \quad 2p: \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \quad 3s: \underline{\uparrow\downarrow} \quad 3p: \underline{\uparrow\quad} \underline{\uparrow\quad} \underline{\uparrow\quad}$$
  • Noble-gas-core abbreviation: $$[\text{Ne}] 3s^2 3p^3$$ The noble gas preceding phosphorus is Neon (Ne), which has 10 electrons ($1s^2 2s^2 2p^6$).

• b) Chlorine (Cl) Chlorine has an atomic number of 17, meaning it has 17 electrons.

  • spdf notation: $$1s^2 2s^2 2p^6 3s^2 3p^5$$
  • Orbital diagram: $$1s: \underline{\uparrow\downarrow} \quad 2s: \underline{\uparrow\downarrow} \quad 2p: \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \quad 3s: \underline{\uparrow\downarrow} \quad 3p: \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \underline{\uparrow\quad}$$
  • Noble-gas-core abbreviation: $$[\text{Ne}] 3s^2 3p^5$$ The noble gas preceding chlorine is Neon (Ne), which has 10 electrons ($1s^2 2s^2 2p^6$).

• c) Chloride ion ($\text{Cl}^-$) A chloride ion has gained one electron compared to a neutral chlorine atom. So, it has $17 + 1 = 18$ electrons.

  • spdf notation: $$1s^2 2s^2 2p^6 3s^2 3p^6$$
  • Orbital diagram: $$1s: \underline{\uparrow\downarrow} \quad 2s: \underline{\uparrow\downarrow} \quad 2p: \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \quad 3s: \underline{\uparrow\downarrow} \quad 3p: \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \underline{\uparrow\downarrow}$$
  • Noble-gas-core abbreviation: $$[\text{Ne}] 3s^2 3p^6 \quad \text{or simply} \quad [\text{Ar}]$$ The noble gas preceding $\text{Cl}^-$ (with 18 electrons) is Neon (Ne). The configuration is also identical to that of Argon (Ar).

• d) Aluminum ion ($\text{Al}^{2+}$) Aluminum has an atomic number of 13, meaning a neutral atom has 13 electrons. The $\text{Al}^{2+}$ ion has lost two electrons, so it has $13 - 2 = 11$ electrons. Electrons are removed from the highest principal quantum number shell first, and then from the subshell with the highest $l$ value within that shell. Neutral Al: $1s^2 2s^2 2p^6 3s^2 3p^1$. First electron removed from $3p$. Second electron removed from $3s$.

  • spdf notation: $$1s^2 2s^2 2p^6 3s^1$$
  • Orbital diagram: $$1s: \underline{\uparrow\downarrow} \quad 2s: \underline{\uparrow\downarrow} \quad 2p: \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \underline{\uparrow\downarrow} \quad 3s: \underline{\uparrow\quad}$$
  • Noble-gas-core abbreviation: $$[\text{Ne}] 3s^1$$ The noble gas preceding $\text{Al}^{2+}$ (with 11 electrons) is Neon (Ne), which has 10 electrons ($1s^2 2s^2 2p^6$).