E

A. Yes, they have same electron numbers. B. Yes, they have same electron arrangement.

C. No, sodium ion is still a form of sodium, not atom but cations. D. No, sodium ion is a charged particle, while the neon atom is a neutral one.

E. C and D.

5. It is impossible for Tom to judge such important affair B

A. as a rule of thumb. B. by rule of thumb. C. though a rule of thumb. D. by experiment.

6. What happens during Na + Cl Na+Cl- D

A. the nuclei of each ions are changed. B. the inner energy level of electrons changed. C. A and B.

D. The outermost energy level is altered.

7. Is there any order or any pattern to the way that the electron dot are draw? C

A. No, there is no any order. B. Yes, the p orbitals are filled firstly.

C. Yes, the s orbital is filled firstly and the p orbitals.

D. Yes, but the p orbitals is filled willfully. V. Translation

Chlorine is more electronegative than hydrogen. In a hydrogen chloride molecule, the chlorine atom has a much greater attraction than the hydrogen atom for the shared electron pair. Because the shared electron are held more tightly by the chlorine atom, the chlorine end of the molecule is more negative than the hydrogen end. If you think of an orbital as a fuzzy-looking cloud, then the cloud is denser near the chlorine atom. When the electrons in a covalent bond are not equally shared, the bond is said to be polar. Thus the bonding in hydrogen chloride is described as polar covalent. Whereas the bonding in the hydrogen molecule or in the chlorine molecule in nonpolar covalent. The polar covalent bond is not an ionic bond. In an ionic bond, one atom completely losed an electron. In a polar covalent bond, the atom at the positive end of the bond (hydrogen in HCl) still gas some share in the bonding pair of electrons. To distinguish this arrangement from that in an ionic bond, the following notation is use.

The line between the atoms represents the covalent bond, a pair of shared electrons. The δ+ and δ- signify which end is partially positive and which is partially negative (the word partially is used to distinguish this charge from the full charge on an ion).

氯比氢的电负性更大。在氯化氢分子中，氯对共用电子对的吸引力比氢更大。由于共用电子对被氯牢牢控制，氯一端的负电性比氢一端更强。如果把轨道想象成云朵，在氯一端云朵的密度更大。当共价键中的电子不是完全分享时，键称为极性键。在氢分子和氯分子中的键为非极性键。极性共价键不是离子键。在极性键中，原子完全失去电子。在极性键中位于正电一端的原子仍然分享共用电子。为了表示与离子键的区别，用下面的图表示。

原子之间的键表示共价键，一对共用电子。δ+和δ-表示带部分正电或部分带负电的一端（部分这个词时为了表示与离子键的不同）。