A:①②③
B:②③④
C:①②④
D:①③④
元素编号
元素性质与原子(或分子)结构
T
最外层电子数是次外层电子数的3倍
X
常温下单质分子为双原子分子,分子中含有3对共用电子对
Y
M层比K层少1个电子
Z
第三周期元素的金属离子中半径最小
— Oh, I’m feeling tired and sleepy now.
It's Sunday today. Sam and his friends are washing(洗)a car for Mr. Green. They can give the money from the car washing to their school football team. Mary and her friends are seeing a funny movie. They see an interesting cat in the movie. Ann is in the park with her mother. They're talking under a big tree. I think they are having a good time. Joan wants to know what her friend is doing. Her friend is in Japan, so Joan is writing a letter to her friend on her computer. May is cleaning the house with her parents. The family are very busy, but they're very happy. They are working and singing.