A. Oxygen and nitrogen. B. Hydrogen and helium. C. Carbon and oxygen. D. Iron and copper. 相关知识点: 试题来源: 解析 B。解析:文中“As the universe expanded and cooled, these particles began to combine to form atoms. The first atoms to form were mainly hydrogen and helium.”明确指出...
A. Silicon atoms. B. Carbon atoms. C. Oxygen atoms. D. Hydrogen atoms. 相关知识点: 试题来源: 解析 B。解析:文章中明确提到“Graphene is an extremely thin and strong material. It is made up of a single layer of carbon atoms arranged in a hexagonal lattice.”,石墨烯是由一层碳原子组...
So, for example, in water we know that there are twice as many hydrogen atoms as oxygen atoms (H2O), making a ratio of 2:1. In salt (sodium chloride) there are equal numbers of sodium and chlorine atoms (NaCl), so the ratio is 1:1. We can easily explain this if chemical ...
All lipids are made up of the same atoms: carbon (C), hydrogen (H) and oxygen (O). Lipids contain the same elements that make up carbohydrates but in different proportions. Lipids have a large proportion of carbon and hydrogen bonds and a small proportion of oxygen atoms. Although the st...
What is the role of the oxygen atoms of the CuO chains in the high-Tc superconductivity of YBa2Cu3O7−δ?doi:10.1016/S0038-1098(97)00040-9A. high-Tc superconductorsA. thin filmsD. charge distribution in (1 2 3)For the YBa2Cu3O7 and YBa2Cu3O6 systems ab initio Hartree-Fock ...
What are atoms and elements, and how do they differ? What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? How many neutrons are in a typical oxygen atom? What is the atomic mass of californium?
Here on earth, vast numbers of hydrogen atoms are contained in water, plants, animals and, of course, humans. But while it’s present in nearly all molecules in living things, it’s very scarce as a gas – less than one part per million by volume. ...
How many protons and neutrons are in mendelevium? What is the number of neutrons in sulfur? What is the mass (in grams) of SO3 that contains 2.61 x 1023 oxygen atoms? How many neutrons does carbon-12 have? What element has 53 protons and 74 neutrons? Which atom has the largest nu...
Where can oxygen be found? Byanon109556— On Sep 08, 2010 what are molecules and atoms? Byanon86505— On May 25, 2010 why can't you see or taste oxygen? Byanon73095— On Mar 25, 2010 why is oxygen not seen? Byanon73094— On Mar 25, 2010 ...
Coming in at No. 3 is hydrogen. There are more hydrogenatomsin the human body than any other element, but it makes up just 9% to 10% of our bodies by mass. Hydrogen is the other element in H2O, and there are two hydrogen atoms for every oxygen atom. Plus, hydrogen is a key comp...