Q. \( \mathrm{BaCl_2} \) lewis structure

Below is how to draw the Lewis structure for BaCl₂ step by step, including the reasoning you would use as a chemistry tutor.

Step 1: Identify the type of compound

BaCl₂ is an ionic compound made from barium (Ba) and chlorine (Cl).

Barium is in Group 2, so it tends to form a +2 ion.

Chlorine is in Group 17, so it tends to form a -1 ion.

Step 2: Determine ionic charges

For barium:

\[ \text{Ba} \rightarrow \text{Ba}^{2+} \]

For chlorine:

\[ \text{Cl} \rightarrow \text{Cl}^{-} \]

Since there are two chlorine atoms in BaCl₂, you balance charge:

\[ \text{Ba}^{2+} + 2(\text{Cl}^{-}) \]

So the compound is represented as:

\[ \text{BaCl}_2 \equiv \text{Ba}^{2+} + 2\text{Cl}^{-} \]

Step 3: Use valence electrons of each ion to place dots

Chlorine has 7 valence electrons as a neutral atom. When it becomes \(\text{Cl}^-\), it gains one electron to complete its octet.

So each \(\text{Cl}^-\) has:

\[ 8 \text{ valence electrons} \]

That means each chloride ion has an octet, typically shown as 4 lone pairs (8 electrons) around the Cl.

Step 4: Determine what to draw for Ba

Barium forms \(\text{Ba}^{2+}\), meaning it has lost its valence electrons in the ionic picture.

Therefore, Ba is shown as:

\[ \text{Ba}^{2+} \]

and it does not have lone pairs drawn on it (because it is a cation with a stable electron configuration, not an atom keeping bonding electrons as dots).

Step 5: Write the Lewis structure (ionic Lewis structure)

The Lewis structure for BaCl₂ is typically drawn as \(\text{Ba}^{2+}\) with two \(\text{Cl}^-\) ions, each having 4 lone pairs.

Final Lewis structure (text description)

\(\text{Ba}^{2+}\) sits in the center, and two \(\text{Cl}^-\) are placed around it.

Each \(\text{Cl}^-\) has four lone pairs.

Final structure in symbolic Lewis form

\[ \text{Ba}^{2+}\ \ \ \ \ :\text{Cl}:\ \ \ \ \ \ :\text{Cl}: \]

Now specify the lone pairs on each chlorine as 4 pairs total:

Each \(\text{Cl}^-\) has:

• \(4\) lone pairs shown as dots around Cl.

• The ion charge marked as \( – \).

Important note about how lone pairs are usually pictured

On a diagram, each \(\text{Cl}\) would be surrounded by 8 dots (4 lone pairs), and the overall ions are shown with charges:

• \(\text{Ba}^{2+}\)

• \(\text{Cl}^{-}\) with 4 lone pairs on each chlorine

Answer (Lewis structure)

BaCl₂ Lewis structure: \(\text{Ba}^{2+}\) with two \(\text{Cl}^{-}\) ions. Each \(\text{Cl}^{-}\) has 4 lone pairs (8 valence electrons) and is typically shown with dots around the Cl.