The acetate ion has the formula \(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}^{-}\). Draw a dot diagram for it given the following atomic connections. (Hint: Watch for resonance forms.)

We will first find the total number of valence electrons in the acetate ion: Carbon (C) has 4 valence electrons each, and there are 2 Carbon atoms, hence total: 4 * 2 = 8 electrons. Hydrogen (H) has 1 valence electron each, and there are 3 Hydrogen atoms, hence total: 1 * 3 = 3 electrons. Oxygen (O) has 6 valence electrons each, and there are 2 Oxygen atoms, hence total: 6 * 2 = 12 electrons. Since the acetate ion carries a negative charge, we need to add 1 more electron as the extra electron in the negative ion. Total valence electrons: 8 + 3 + 12 + 1 = 24 electrons.

The given atomic connections are: Both carbon atoms are bonded to Oxygen atoms, and the three Hydrogen atoms are connected to one of the Carbon atoms. We will place the oxygen atoms on either side of the carbon atoms and connect the three hydrogen atoms to the other carbon atom.

Now, for each bond between two atoms, we assign two shared electrons. Carbon-1 is connected to 3 Hydrogen atoms and Carbon-2: - 2 * 1 (C1 and H) = 2 electrons (3 bonds) - 2 * 1 (C1 and C2) = 2 electrons Carbon 2 is connected to Carbon-1 and 2 Oxygen atoms: - 2 * 1 (C2 and O1) = 2 electrons - 2 * 1 (C2 and O2) = 2 electrons So far, we have used: 2 + 2 + 2 + 2 = 8 electrons, and there are 16 electrons left to distribute (24 - 8). Now we will distribute the remaining 16 electrons to the outer-shell atoms satisfying the octet rule. - For 2 Oxygen atoms: 2 * 6 = 12 electrons remain to distribute around 2 oxygens - For Carbon-2: 4 electrons are required (as there are already 4 shared electrons) We can place 6 electrons (3 lone pairs) around each oxygen atom and place the last 2 electrons as a lone pair around Carbon-2.

Now, We have a single bond between Carbon-2 and Oxygen-1, and we have a single bond between Carbon-2 and Oxygen-2 with three lone pairs around both oxygen atoms. Examining for resonance, we can move one of the lone pairs from Oxygen-1 to form a double bond with Carbon-2, turning the double bond between Carbon-2 and Oxygen-2 into a single bond, and one of the lone pairs from Oxygen-2 moves to become the remaining lone pair around Carbon-2. This is a valid resonance form, and both structures contribute to the final Lewis structure of the acetate ion.

Finally, the Lewis structure of the acetate ion consists of two resonance structures: Structure 1: - Carbon-1 connected to 3 Hydrogen atoms and Carbon-2 (single bond) - Carbon-2 connected to Oxygen-1 (double bond) with two lone pairs, and connected to Oxygen-2 (single bond) with three lone pairs - Carbon-2 has one lone pair. Structure 2: - Carbon-1 connected to 3 Hydrogen atoms and Carbon-2 (single bond) - Carbon-2 connected to Oxygen-2 (double bond) with two lone pairs, and connected to Oxygen-1 (single bond) with three lone pairs - Carbon-2 has one lone pair. These 2 resonance structures represent the Lewis structure of the acetate ion.