Question

question 1
1 pts
which of the following does not have an angular shape?
$n_3^-$
$s_3^{2-}$
$hocl$
$clo_2^-$
question 2
1 pts
what are the angles in a trigonal planar geometry?
none of these
$120^circ$
$90^circ$
$180^circ$
question 3
1 pts
the basic fact that determines molecular shapes is that
electrons attract each other
electron pairs repel each other
nuclei attract electrons
nuclei repel each other

Explanation:

Question 1

Step1: Determine molecular geometry using VSEPR theory.

For \(N_3^-\): The central N atom has 2 bonding pairs (linear structure, no lone pairs), so linear shape (not angular).
For \(S_3^{2-}\): Central S has 2 bonding pairs and 1 lone pair (angular/bent).
For \(HOCl\): O is central, with 2 bonding pairs (H and Cl) and 2 lone pairs? Wait, no: O has 2 bonding (H - O and O - Cl) and 2 lone pairs? Wait, actually, \(HOCl\) has O as central, with 2 bonding pairs (H and Cl) and 2 lone pairs? No, VSEPR: O has 6 valence electrons, bonds to H (1) and Cl (1), so 2 bonding, 2 lone pairs? Wait, no, \(HOCl\) structure: H - O - Cl. O has 2 bonding pairs (H and Cl) and 2 lone pairs? Wait, no, O has 6 valence electrons: 2 in bonds (H - O and O - Cl), so 4 non - bonding (2 lone pairs). So electron geometry tetrahedral, molecular geometry bent (angular).
For \(ClO_2^-\): Cl is central, with 2 bonding pairs (O) and 1 or 2 lone pairs? Cl has 7 valence, plus 1 (from charge), total 8. Bonds to 2 O: 4 electrons, so 4 non - bonding (2 lone pairs). Electron geometry tetrahedral, molecular geometry bent (angular).

Step2: Identify the non - angular (linear) species.

\(N_3^-\) has linear geometry (no lone pairs on central atom, 2 bonding pairs), so it does not have angular shape.

Step1: Recall trigonal planar geometry.

Trigonal planar geometry has three atoms bonded to a central atom, all in the same plane. The bond angles in a trigonal planar molecule (e.g., \(BF_3\)) are \(120^\circ\) because the three bonding pairs are arranged as far apart as possible in a plane, leading to equal angles between each pair.

Step2: Select the correct angle.

Among the options, \(120^\circ\) is the bond angle for trigonal planar geometry.

Step1: Recall VSEPR theory.

The Valence - Shell Electron - Pair Repulsion (VSEPR) theory states that electron pairs (bonding and non - bonding) around a central atom repel each other. This repulsion determines the molecular shape as the electron pairs try to get as far apart as possible.

• "Electrons attract each other" is incorrect (electrons have the same charge and repel).
• "Nuclei attract electrons" is true (electrostatic attraction), but it does not determine molecular shape.
• "Nuclei repel each other" is true (positive charges repel), but not the main factor for molecular shape.
• "Electron pairs repel each other" is the key principle of VSEPR, which determines molecular shapes.

Step2: Choose the correct option.

Based on VSEPR theory, electron pairs (bonding and lone pairs) repel each other, which determines molecular shapes.

Answer:

\(N_3^-\) (the option with \(N_3^-\))

Question 2