如图是几种元素的原子结构示意图和氖元素在元素周期中的信息．

（1）钠元素和氧元素的本质区别是 ____．

（2）氧原子容易 ____（填“得到”或“失去”）电子．

（3）写出钠元素和硫元素形成化合物的化学式： ____．

（4）氖元素的相对原子质量是 ____．

从对话后的方框中选择适当的选项补全对话
Ted: What's the best restaurant in town?
Kay: What kind of food do you like?
Ted: ____ 
Kay: Well, the French Deli is really good.
Ted: ____ 
Kay_: Yes, it's the most expensive restaurant in town. But it has the best service, too.
Ted:____ 
Kay: It's cheaper than the French Deli, but the food is kind of boring.
Ted: ____ 
Kay: Oh, that's a new place. It's the most popular restaurant in town.
Ted: Is the food good?
Kay: Yeah, if you like hot curry.
Ted:Yeah. I love it! Let' s go there.

计算$\sqrt{3}$×$\sqrt{5}$的结果是（　　）