下列叙述中正确的是
A．原子及其离子的核外电子层数等于该元素所在周期数
B．稀有气体元素原子的最外层电子数都是8
C．元素周期表从ⅢB到ⅡB 10个纵行的元素都是金属元素
D．短周期元素中，若两种元素的原子序数相差8，则它们的周期数一定相差1
CD
原子与阳离子的核外电子层数不相等，阴离子与原子的核外电子层数相等。稀有气体元素原子的最外层电子数一般为8，但是氦为2.
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| Living and dealing with kids can be a difficult job, but living and dealing with parents can be even more difficult. If I have learned anything in my 16 ears, it is that 1 is very important, 2 when you disagree. With any relationship, you need to let other people know how you're 3 . When you're mad at your parents, or anyone else, not talking to them doesn't 4 anything. Communication 5 the concerns (所关注的事) of another. It means that you can't 6 come home from school, go up to your room and ignore (不理睬) everyone. 7 you just say "Hi", and see how their day was for five minutes, it is better than nothing. When 8 with parents, you always have to make them feel good about how they are doing 9 parents. If you are 10 to make them see something as you see it, tell that you'll listen to what they have to say, but ask them 11 to listen to you. Shouting or walking away only makes the situation 12 . This is an 13 : one night, Sophie went to a street party with her friends. She knew she had to be home by 14 , but she didn't feel she could jus 15 to go home. That would be rude. 16 , the had been nice enough to make her along with them. Needless to say, she was late getting home. Her parents were 17 at first, but when Sophie explained why she was late, they weren't as mad and let the incident go. Communication was the key factor here. If Sophie's parents had not been willing to 18 , Sophie would have been in a lot of trouble. Communication isn't a(n) 19 way deal, it goes both ways. Just remember, if you get into a 20 like Sophie's, tell the other person how you feel-listening is a key factor in communication. | ||||
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