什么是质子?定义、发现、特征
电子是使用阴极射线管发现的。电流从阴极(负极)流向阳极(正极)。几个实验表明,粒子在阴极发射,这些粒子带负电荷。这些实验证明了电子的存在。如果阴极射线是阴极金属原子释放的电子,那么失去这些电子的原子还剩下什么?
我们知道一些关于电荷的基本知识。它们由物质粒子携带。密立根的实验表明,它们以单个基本单位的整数倍的形式存在。原子没有总电荷,这意味着每个原子都包含完全相同数量的带正电和带负电的粒子。氢原子是最简单的原子,只有一个电子。如果那个单个电子从氢中移除,那么原子的剩余部分只是一个带正电的粒子。
什么是质子?
The proton is the positively charged subatomic particle present in all atoms. The mass of the proton is about 1840 times the mass of the electron
电荷是某些粒子的属性,例如电子(-)、质子(+)和夸克(是的,夸克),它描述了它们如何相互作用。有两种不同类型的电荷,有点武断地命名为正电荷和负电荷(很像四个基本方向被命名为北、南、东和西)。
一般来说,携带相同类型电荷的粒子相互排斥,而携带相反电荷的粒子相互吸引。在每个原子内,核内的质子吸引核外的电子。
质子的发现
1886 年,Eugene Goldstein (1850–1930) 发现了这种带正电粒子存在的证据。使用在阴极上有孔的阴极射线管时,他注意到有射线以与阴极射线相反的方向传播。他称这些运河射线并表明它们是由带正电的粒子组成的。
原子核是欧内斯特·卢瑟福于 1911 年在他著名的金箔实验中发现的。他得出结论,原子中所有带正电的粒子都集中在一个奇异的核心中,并且原子的大部分体积是空的。他还指出,原子核中带正电的粒子总数等于其周围存在的带负电的电子总数。为了支持他的理论,他进行了一项著名的实验,称为金箔实验。
Gold Foil Experiment
Rutherford, in his experiment, directed high-energy streams of α-particles from a radioactive source at a thin sheet (100 nm thickness) of gold. In order to study the deflection caused to the α-particles, he placed a fluorescent zinc sulfide screen around the thin gold foil. Ernest Rutherford selected a gold foil for his experiments because he wanted as thin a layer as possible, and gold is very highly malleable.
- Results:
- Most of the particles pass through the foil without any deflection.
- Some of the alpha particles deflect at small angles.
- Very few even bounce back (1 in 20,000).
- Conclusion: Based on his observations, Rutherford proposed the following structural features of an atom:
- Most of the atom’s mass and its entire positive charge are confined in a small core, called the nucleus. The positively charged particle is called a proton.
- Most of the volume of an atom is empty space.
- The number of negatively charged electrons dispersed outside the nucleus is the same as the number of positive charges in the nucleus. It explains the overall electrical neutrality of an atom.
质子的特征
- 质子带正电。
- 质子位于原子核内部。
- 质子的静止质量为 1.67262 × 10−27 kg(~ 1 amu,是电子质量的 1.836 倍。
- 1 个质子的电荷为 1.6 x 10-19 C。1 库仑等于 6.241 x 1018 个质子的电荷。
- 质子还具有使阳极粒子流动的能力。
亚原子粒子之间的表格比较:电子、质子和核: Particle Symbol Actual Mass Relative Mass Relative Charge Location Proton p/p+ 1.67 × 10–24 g 1 +1 Inside Nucleus Electron e/e- 9.1 × 10–28 g 0.0005 -1 Outside Nucleus Neutron n 1.67 × 10–24 g 1 0 Inside Nucleus
示例问题
问题 1:在卢瑟福实验中,为什么大多数 α 粒子会直接穿过箔片?
解决方案:
Most of the alpha particles go straight through the foil in the Rutherford experiment because most of the part of the atom is empty.
问题 2:卢瑟福的实验中使用了哪种类型的辐射?
解决方案:
The α particle was bombarded on thin gold foil and observed that the nucleus occupies a very small portion of the atom.
问题 3:卢瑟福为他的 α 粒子散射实验选择了哪种金属,为什么?
解决方案:
Because gold is the most malleable metal and can be hence beaten down to get very thin sheets. The sheet of gold foil Rutherford used was only 1000 atoms thick. Gold’s malleability made it possible for it to be beaten down to such a thin sheet.
问题 4:质子的相对质量和电荷是多少?
解决方案:
Protons have a positive electrical charge of one (+1) and a mass of 1 atomic mass unit (a.m.u.), which is about 1.67 × 10−27 kilograms.
问题5:质子的父亲是谁,谁发现了质子?
解决方案:
Ernest Rutherford is the father of Proton, who discovered the proton in his famous experiment with gold foil in 1909.
问题 6. 质子里面是什么?
解决方案:
The proton, one of the atomic nuclei parts, consists of basic particles called quarks and gluons.