• 2022-05-30 问题

    Atoms having the same atomic number Z, but different numbers of neutrons N are called of the element A: nuclei B: isotopes C: units D: masses

    Atoms having the same atomic number Z, but different numbers of neutrons N are called of the element A: nuclei B: isotopes C: units D: masses

  • 2022-06-07 问题

    Which of the following is the physical properties of hydrogen? A: low density B: The boiling point of hydrogen is about -253 ℃. C: It has three isotopes. D: It reacts with oxygen to form water. E: It can react with [img=47x22]1803a8273e77b4a.png[/img] to form [img=34x19]1803a827468c498.png[/img]. F: It reacts with nitrogen to form ammonia. G: It can react with CO to form methane. H: It can react with [img=33x22]1803a8274f0cd41.png[/img] to form CO.

    Which of the following is the physical properties of hydrogen? A: low density B: The boiling point of hydrogen is about -253 ℃. C: It has three isotopes. D: It reacts with oxygen to form water. E: It can react with [img=47x22]1803a8273e77b4a.png[/img] to form [img=34x19]1803a827468c498.png[/img]. F: It reacts with nitrogen to form ammonia. G: It can react with CO to form methane. H: It can react with [img=33x22]1803a8274f0cd41.png[/img] to form CO.

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