Final answer:
Lewis symbols for ions include the element's symbol with dots representing valence electrons. Anions have extra dots for gained electrons, while cations have fewer or no dots due to lost electrons. The ions Cl⁻, Mg²⁺, O²⁻, and Al³⁺ each have Lewis symbols reflecting their respective valence electron counts after ionization.
Step-by-step explanation:
The question asks us to write the Lewis symbols for each of the following ions: a) Cl⁻ b) Mg²⁺ c) O²⁻ d) Al³⁺. Lewis symbols represent the valence electrons of an element or ion surrounding the element's chemical symbol. The elemental symbol is at the center with dots around it to represent electrons. Negative ions (anions) have extra electrons while positive ions (cations) have fewer electrons than the neutral atoms.
- a) Cl⁻: The neutral chlorine atom has 7 valence electrons, and as Cl⁻, it has gained one extra electron, bringing it to a total of 8 valence electrons. The Lewis symbol is Cl with 8 dots around it, representing a filled valence shell.
- b) Mg²⁺: The neutral magnesium atom has 2 valence electrons, and as Mg²⁺, it has lost these electrons, having none in its Lewis symbol. So the Lewis symbol for Mg²⁺ is Mg with no dots around it.
- c) O²⁻: The neutral oxygen atom has 6 valence electrons, and as O²⁻, it has gained two extra electrons for a total of 8 valence electrons. The Lewis symbol is O with 8 dots representing a filled valence shell.
- d) Al³⁺: The neutral aluminum atom has 3 valence electrons, and as Al³⁺, it has lost all three electrons, and its Lewis symbol will be Al with no dots around it.