Mandy:Hello, Jessica. Long time no see.Jessica:Hi, Mandy. Wow, you look great! Have you changed something about yourself?Mandy:(1)_______________________________________________.Jessica:Nice. Can you tell me which one?Mandy:The one over on Oak Street.Jessica:(2)________________________________________________Mandy:Let me see… I got a manicure, a pedicure and a facial. Then I had a massage and dyed my hair.Jessica:Sounds expensive.Mandy:(3)________________________________________________Jessica:Hey… What are you doing?Mandy:I'm taking a selfie (自拍). I want to post it to Facebook and show everyone the "new" me.Jessica:Cool! You look awesome!
NaCl、NaBr、MgO和BaO四种晶体中离子键从强到弱的顺序为:
A. NaCl>NaBr>MgO>BaO
B. NaBr>MgO>BaO>NaCl
C. MgO>BaO>NaCl>NaBr
D. BaO>MgO>NaCl>NaBr
下列关于离子键的说法正确地是:
A. 当两种元素电负性差值>1.7时,形成的化学键倾向于离子键
B. 离子晶体中的离子键就是一个正离子和一个负离子之间的静电引力
C. 离子键键能的大小与离子半径、离子电荷有关
D. 离子键具有饱和性和方向性
下列关于化学键的说法,正确的是:
A. 原子之间的相互作用都是化学键
B. 只有在相邻的两个原子间才能形成化学键
C. 化学键就是原子间的吸引作用
D. 化学键包括原子间相互吸引和排斥两方面的强烈作用