What is the name for the shape of the molecular ion of Br3-12

What is the name for the shape of the molecular ion of Br3-12? Tetrahedral Linear Trigonal planar Seemgam?

The Correct Answer and Explanation is:

The molecular ion of Br3-12 is most likely referring to Br3- (tribromide ion) which typically forms a linear molecular geometry.

Explanation:

In the case of Br3-, it consists of three bromine atoms bonded together with an extra electron (due to the negative charge), giving it a formal charge of -1. To determine its molecular geometry, we apply the principles of the Valence Shell Electron Pair Repulsion (VSEPR) theory.

  1. Electron Domain Count:
    The central atom (in this case, bromine) has two bonding regions (one to each of the other bromine atoms) and a third bonding region (from the extra electron). This means there are three bonding regions around the central bromine atom.
  2. Electron Geometry:
    Since there are three bonding regions, the ideal geometry that minimizes electron pair repulsion is linear.
  3. Molecular Geometry:
    Because the electron pairs around the central bromine atom are arranged in a linear fashion, the molecular geometry of Br3- is also linear.

Why Linear?

A linear geometry occurs when there are only two atoms connected to a central atom, or in this case, three atoms connected in a straight line. The bond angles in this geometry are typically 180°.

In summary:

The molecular geometry of Br3- is linear due to its three bonding regions, which arrange in a straight line to minimize repulsion.

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