题干

下列叙述中正确的是(   )

A:同一主族元素原子序数越大的单质的熔点、沸点也越高

B:除H外,周期表中主族族序数等于周期数的元素全为金属元素

C:同主族的非金属的简单氢化物中最稳定的其熔、沸点也最高

D:同周期的主族元素形成的简单离子的半径从左到右依次减小

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答案(点此获取答案解析)

B

同类题2

根据短文理解,选择正确答案。

    Terrible disasters in the last 50 or 100 years have become increasingly common. Over the last 30 years, the number of weather-related disasters has increased quickly, and the disasters have also affected more people and caused more economic loss. However, much of this could be avoided through disaster risk reduction(DRR降低灾难风险).

    A meeting, held in Sendai, Japan last month, opened one day after Cyclone Pam(飓风Pam)hit Vanuatu, which struck the islands with winds of up to 340km/h and destroyed the island nation. The speech by the President of Vanuatu was given shortly after that. He begged the international community for support and stronger commitment (承诺)to helping them manage climate and disaster risks. In the face of disasters, it is always the developing countries that suffer most. Damage in these countries is often worse and unluckily, there is limited money and technique to prevent these disasters.

    In fact, we have seen Asian countries-especially those that have suffered a lot in disasters can't pay the price. Great loss Asia has suffered comes to a total of almost $ 53 billon yearly over the past 20 years.

    At the same time, studies have shown once again that proper prevention saves lives and damage. With this in mind, people at the Sendai meeting were able to come up with new agreements that effective ways of disaster risk reduction will be carried out in the coming years for those who easily get damaged in disasters.