问题
选择题
下列粒子中属于原子,且具有稳定结构的是:
答案
C
题目分析:原子中质子数等于核外电子数,稳定结构为最外层8电子或2电子的结构,故符合题意的为C
下列粒子中属于原子,且具有稳定结构的是:
C
题目分析:原子中质子数等于核外电子数,稳定结构为最外层8电子或2电子的结构,故符合题意的为C
书面表达。|
1. 词数:100左右; 2. 参考词汇:优惠的会员费 reduced membership fee 额外收费 extra charge 3. 信的开头和结尾已为你写好,不计入总词数。 Dear Sir/ Madam, I'm writing to you with regard to your advertisement published in the magazine “Panorama”. _____ _____________________________________________________________________________ I am looking forward to hearing from you at your earliest convenience. Yours faithfully, Li Hua |