百度试题 结果1 题目What are the two most common elements in the earth's crust? A. Carbon and nitrogen B. Hydrogen and helium C. Iron and nickel D. Silicon and oxygen 相关知识点: 试题来源: 解析 D 反馈 收藏
Helium-4, which is the most common isotope of helium has two protons and two neutrons in its nucleus. A common hydrogen atom has no neutrons although hydrogen does have isotopes where neutrons are part of the nucleus.doi:10.1007/978-3-319-15123-6_1Springer International Publishing...
It took 380,000 years for the universe to cool enough to slow down the electrons so that the nuclei could capture them to form the first atoms. The earliest atoms were primarilyhydrogenandhelium, which are still the most abundant elements in the universe, according toJefferson Lab. Gravity ev...
Heliumis a light, inert gas used for MRI machines, cryogenic research, "heliox" (a mixture of helium and oxygen), and helium balloons. You might have heard that inhaling helium can be dangerous, sometimes even fatal, but have you ever wondered how likely you are to harm your health breath...
Answer to: Using what you know about the Bohr model and the structure of hydrogen and helium atoms, explain why the line spectra of hydrogen and...
I am wondering about this. It is a familiar sight, the orbital diagrams for the hydrogen atom, depictions of which are abundant and so are not in need of reproduction here. However, what about the "orbitals" for bigger, more complex atoms, say, Helium? I inquired ...
wordstome.Ihadnoideawhathydrogenwas,andI didn?treally wanttoknow,eitherIfounditallso 45. (bore)and difficult.But Mr Jenkins madeeverythinginteresting.Heusedtoexplainthings whichseemeddifficultwithlotsofpractical46. (example)andinsimplelanguage.Oneday,he tookusoutsideandwe47. (build)arocket! Irememb...
What Are Some Examples of Atoms? The periodic table of elements lists all the atoms that are currently known and available. Being that the elements are the most basic and simplified form of any substance, all elements are atoms. Some examples are helium, oxygen and hydrogen. ...
The life of a star, no matter its size, is a balancing act between the inward "push" of gravity and the outward push provided by photons generated as they conductnuclear fusion, the forging of heavy atomic nuclei from light nuclei, at their cores. When stars run out of hydrogen to fuse...
Fusionis the combining of two small atoms such as Hydrogen or Helium to produce heavier atoms and energy. These reactions can release more energy than fission without producing as many radioactive byproducts. Fusion reactions occur in the sun, generally using Hydrogen as fuel and producing Helium...