根据右表判断，下列说法正确的是（ ）
A．铝的相对原子质量是13
B．钠离子核外有三个电子层
C．第二、三周期元素的原子从左至右最外层电子数逐渐增多
D．在化学变化中镁元素容易失去最外层2个电子形成镁离子
答案：C
铝的核电荷数为13，而不是相对原子质量是13，故A错；钠离子的结构示意图为 ，含有两个电子层，故B错；根据表中信息，第二、三周期元素的原子从左至右最外层电子数逐渐增多，故C正确；在化学变化中镁原子容易失去最外层2个电子形成镁离子，而不是镁元素失去电子，故D错。
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| My uncle John used to live in a beautiful little house by the sea in Atlantic City. I say he "used to" live there 1 he doesn't live there any more. He was killed two years ago. Uncle John wrote novels. He not only 2 his job, but also made a lot of money by doing it. When he died, he had $60 million in the bank. After Uncle John's death, I came to stay in his house for a while. I had been there for two days when I 3 a message on the screen of the old computer. I was very surprised, because I thought the computer had been 4 . The message said, "You have new 5 !" When I read it, I thought it looked like the 6 of a novel. "This looks interesting. " I thought, "It must be 7 one of Uncle John's friends." I decided I should make an answer to the e-mail to tell him or her that Uncle John was 8 . However, the computer would not let me 9 . Every day for the next three weeks, more e-mails kept arriving. I printed 10 of all of them. The story was about Jane Winterbourne, a young writer working on her first novel. She sent her novel to Jack Tanner, an old writer and asked him to 11 her to publish it. However, he cheated her, and published the novel himself pretending that he had 12 it. The novel was very 13 . Tanner made a lot of money, and bought himself a house by the sea in Atlantic City. It was then that I realized that "Jack Tanner" and "Jane Winterbourne" were 14 names. "Jack" was 15 to be Uncle John. | ||||
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