题干

下列有关电子云和原子轨道的说法正确的是

A:原子核外的电子象云雾一样笼罩在原子核周围,故称电子云

B:s能级的原子轨道呈球形,处在该轨道上的电子只能在球壳内运动

C:p能级的原子轨道呈纺锤形,随着能层的增加,p能级原子轨道也在增多

D:与s电子原子轨道相同,p电子原子轨道的平均半径随能层的增大而增大

上一题 下一题 0.0难度 选择题 更新时间:2019-04-27 10:26:29

答案(点此获取答案解析)

D

同类题4

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项,选项中有两项为多余选项

    Save Your Time, Money and Stress with Savvy (懂行,悟性)Rental Car Strategies

    Renting a car can be expensive, confusing, and stressful — but it doesn't have to be. Here are several helpful strategies to save money, time, and stress on your next (and every) car rental.

Sign Up for Loyalty Programs

    Rental car loyalty programs are free to join, so register for any programs you might use in the future. My favorite car rental loyalty program benefit is that I can skip the counter and head right to my reserved car. Some programs allow members to choose a car from the available pool. ____

Optimize Your Strategy

    Do you really need a rental car from the airport? For instance, if your flight arrives at night, take a free hotel shuttle and pick up your car the next day. The car rental location might even be at your hotel or can pick you up (or deliver the car to you).____

____

    For a city trip, you may not even need a rental car. Research whether mass transit(运输), taxi, Uber, bike rental, and other transportation methods will suffice(足够). Parking charges at downtown hotels may cost more than your car rental rate, so it may be doubly in your favor to give up a rental car. In some locations, a bike might be more efficient and economical than a car.

 Search for Specials

    ____ In conjunction(结合)with your personal discount code, you may also find a last-minute rate, free rental day, or other promotion. My favorite annual travel deal is driving a car one-way out of Florida after Spring Break with rates as low as $1 per day.

Consider Alternative Rental Options

    Major car rental companies might have an associated discount brand at your rental location, like Firefly for Hertz.____ 

    An independent or smaller local agency may fit your needs; like A1 or Lucky Owl in Honolulu. Many people prefer to check rates on Hotwire and Priceline, especially for last-minute rentals.

A.Rental rates are likely lower away from the airport, plus you might save the cost of an entire rental day.

B.I use discount-finding websites to track my car reservations.

C.Smaller brands, like Thrifty and Fox, might offer better service and lower rates.

D.In addition to saving time and offering freedom of choice, loyalty members earn points and receive special promotions.

E.Check car rental company websites for current specials.

F.Skip the Car

G.Use a bike