Question

Write electron configurations for the most stable ion formed by each of the elements Te, \(\mathrm{Cl}, \mathrm{Sr}\), and \(\mathrm{Li}\) (when in stable ionic compounds).

Short answer

The electron configurations for the most stable ions formed by Te, Cl, Sr, and Li are: Te²⁻: \([Kr] 5s^2 4d^{10} 5p^6\) Cl⁻: \([Ne] 3s^2 3p^6\) Sr²⁺: \([Kr]\) Li⁺: \([He]\)

Step-by-step solution

Determine the number of valence electrons

To do this, we can use the periodic table to determine the group number for each element. The group number indicates the number of valence electrons. Te (Tellurium) - Group 16 - 6 valence electrons Cl (Chlorine) - Group 17 - 7 valence electrons Sr (Strontium) - Group 2 - 2 valence electrons Li (Lithium) - Group 1 - 1 valence electron

Determine the most stable charges for each ion

To form ionic compounds, atoms will lose or gain electrons to achieve a stable electron configuration. Elements in groups 1-3 tend to lose electrons, while those in groups 14-18 tend to gain electrons. Te: Gains 2 electrons to achieve a full outer shell (charge of -2) Cl: Gains 1 electron to achieve a full outer shell (charge of -1) Sr: Loses 2 electrons to achieve a stable electron configuration (charge of +2) Li: Loses 1 electron to achieve a stable electron configuration (charge of +1)

Write the electron configurations for each ion

Now that we know the most stable charges for each ion, we can find their electron configuration. For cations (positive ions), remove the corresponding number of electrons from the neutral atom's configuration. For anions (negative ions), add the corresponding number of electrons to the neutral atom's configuration. Te: Neutral atom electron configuration: [Kr] 5s² 4d¹⁰ 5p⁴ Ion: Te²⁻ [Kr] 5s² 4d¹⁰ 5p⁶ Cl: Neutral atom electron configuration: [Ne] 3s² 3p⁵ Ion: Cl⁻ [Ne] 3s² 3p⁶ Sr: Neutral atom electron configuration: [Kr] 5s² Ion: Sr²⁺ [Kr] Li: Neutral atom electron configuration: [He] 2s¹ Ion: Li⁺ [He]

Electron configurations for the most stable ions

Te²⁻: [Kr] 5s² 4d¹⁰ 5p⁶ Cl⁻: [Ne] 3s² 3p⁶ Sr²⁺: [Kr] Li⁺: [He]