试题来源: 解析 A 选项A中的质子和中子位于原子核内,构成了原子的主要质量,而电子的质量极小,可忽略不计。原子质量数即质子数与中子数之和。选项B和C错误地包含了电子,而选项D虽然所有粒子都包含,但电子贡献微乎其微,因此正确答案为A。反馈 收藏
Define atomic mass of an element in terms of mole concept. View Solution Express unified atomic mass unit in kg. View Solution The energy equivalent of one atomic mass unit is View Solution Energy equivalent of one atomic mass unit is View Solution One unified atomic mass unit represents ...
Atomic mass number of an element is 232 and its atomic number is 90. The end product of this radiaoctive element is an isotope of lead (atomic mass 208 and at
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1. The relative atomic mass of an element is always D I A the mass of an atom of the element relative to %2 the mass of a carbon-12 atom. B the mass of an atom of the element relative to the mass of a hydrogen atom.■ C the weighted mean mass of an atom of the element ...
1 An atom of an element has an atomic number of 6 and a mass number of 12.(a)Using this information, complete the table to show the numbers of protons,neutrons and electrons in one atom of this element.(2)number of protons number of neutrons number of electrons(b)The Periodic Table ...
Element X has three isotopes, ^{22}X, ^{23}X, and ^{25}X. The relative abundances are 60%, 35%, and 5% respectively. What is the average atomic mass foe element X? What two things determine the average atomic mass of an element?
As atomic mass of M is a, 16x of O is attached with 2a of M, therefore 8x of O is attached with (2a/16x)xx8 of M=a/x of M hence. Equivaelent weight of M is a/n.
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