Models of Bonding & Structure B.2 The Covalent Model (id: 2ca9f63bb)

本题目来源于试卷: Models of Bonding & Structure B.2 The Covalent Model，类别为 IB化学

[单选题]
Which correctly states the relative size of the bond angles for $H_2O$, $NH_3$, and $CH_4$?

A. $CH_4$<$NH_3$<$H_2O$
B. $H_2O$<$NH_3$<$CH_4$
C. $H_2O$<$CH_4$<$NH_3$
D. $CH_4$<$NH_3$<$H_2O$


参考答案:  B


本题详细解析:
All three central atoms (N, C, and O) have four electron domains. An increasing number of lone pairs reduces the angle between the bonding pairs.
In CH${}_4$ there are no lone pairs and it has a tetrahedral shape with bond angles of 109.5$\mathrm{°}$.
In NH${}_3$ there is one lone pair and it has a trigonal pyramidal shape with bond angles of 107$\mathrm{°}$.
In H${}_2$O, there are two lone pairs, and it has a bent shape with bond angles of 104.5$\mathrm{°}$.

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