1. VSEPR Theory
(a) NI₃
3 Bonding pairs + 1 lone pair = 4 electron groups
4 electron groups ≡ tetrahedral electron geometry
For molecular geometry, we ignore the lone pair, so the molecular shape is trigonal pyramidal (see Figure 1).
(b) CCl₄
4 bonding pairs = 4 electron groups
4 electron groups ≡ tetrahedral electron geometry
There are no lone pairs, so electron geometry = molecular geometry = tetrahedral (see Figure 2).
(c) BF₃
3 bonding pairs = 3 electron groups
3 electron groups = trigonal planar electron geometry
There are no lone pairs, so electron geometry = molecular geometry = trigonal planar (see Figure 3).
(d) NO₂
⁻
1 single bond + 1 double bond + 1 lone pair = 3 electron groups
3 electron groups = trigonal planar electron geometry
For molecular geometry, we ignore the lone pair, so the molecular shape is bent (see Figure 4)
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2. Structure and physical properties
Answer:
E. The negative side of each water molecule is attracted to the positive side of nearby molecules.
Explanation:
The O-H bonds in water are highly polar, so the H atoms have a partial positive charge, and the O atoms have a partial negative charge.
[tex]\stackrel{\hbox{$\delta^{+}$}}{\hbox{H}}-\stackrel{\hbox{$\delta^{-}$}}{\hbox{O}}-\stackrel{\hbox{$\delta^{+}$}}{\hbox{H }}[/tex]
The partially negative O atom in one molecule is strongly attracted to the partially positive H atom in another molecule, and vice versa.
We call these strong attractive forces hydrogen bonds.
A. Wrong. The partially positive hydrogen atoms repel each other.
B. Wrong. The polarity is a property of the bond. It is not affected by dissolved ions.
C. Wrong. The water molecules are NOT connected to each other by covalent bonds.
D. Wrong. The water molecules haven’t lost or gained electrons.
