Question

given this table of electronegativities: atom electronegativity h 2.2 c 2.6 n 3.0 o 3.4 f 4.0 s 2.6 br 3.0 cl 3.2 p 2.2 i 2.7 list the following molecules in order of increasing dipole moment: ni₃, h₂o, cbr₄, hf

Explanation:

Step1: Recall dipole - moment concept

Dipole moment depends on electronegativity difference and molecular geometry. Non - polar molecules have zero dipole moment.

Step2: Analyze \(CBr_4\)

\(CBr_4\) has a tetrahedral geometry. The electronegativity of \(C = 2.6\) and \(Br=3.0\). Since the molecule is symmetric, the bond dipoles cancel out, and its dipole moment is \(0\).

Step3: Analyze \(NI_3\)

The electronegativity of \(N = 3.0\) and \(I = 2.7\). \(NI_3\) has a trigonal - pyramidal geometry. The electronegativity difference \(\Delta\chi=3.0 - 2.7 = 0.3\).

Step4: Analyze \(H_2O\)

The electronegativity of \(O = 3.4\) and \(H = 2.2\). \(\Delta\chi=3.4 - 2.2=1.2\). \(H_2O\) has a bent geometry, which results in a significant dipole moment.

Step5: Analyze \(HF\)

The electronegativity of \(F = 4.0\) and \(H = 2.2\). \(\Delta\chi=4.0 - 2.2 = 1.8\). \(HF\) is a diatomic polar molecule.

Answer:

\(CBr_4