Question

1. in the lewis structures listed here, m and x represent various elements in the third period of the periodic table. write the formula of each compound using the chemical symbols of each element: (a) m²⁺:x:²⁻ (b) m³⁺:x:⁻₃ (c) m⁺₂:x:²⁻ (d) m³⁺₂:x:²⁻₃

Explanation:

Step1: Determine the elements

Elements in the third period: Na, Mg, Al, Si, P, S, Cl, Ar.

• For \(M^{2 +}\), it could be \(Mg^{2+}\) (since Mg loses 2 electrons).
• For \(X^{2-}\), it could be \(S^{2 -}\) (since S gains 2 electrons).
• For \(M^{3+}\), it could be \(Al^{3+}\) (since Al loses 3 electrons).
• For \(X^{-}\), it could be \(Cl^{-}\) (since Cl gains 1 electron).
• For \(M^{+}\), it could be \(Na^{+}\) (since Na loses 1 electron).

Step2: Write the formulas

• (a) \(MgS\) (using \(Mg^{2+}\) and \(S^{2-}\), charges balance as \(2 + (- 2)=0\)).
• (b) \(AlCl_{3}\) (using \(Al^{3+}\) and \(Cl^{-}\), \(3+3\times(-1) = 0\)).
• (c) \(Na_{2}S\) (using \(Na^{+}\) and \(S^{2-}\), \(2\times1+(-2)=0\)).
• (d) \(Al_{2}S_{3}\) (using \(Al^{3+}\) and \(S^{2-}\), \(2\times3 + 3\times(-2)=0\)).

Answer:

(a) \(MgS\)
(b) \(AlCl_{3}\)
(c) \(Na_{2}S\)
(d) \(Al_{2}S_{3}\)