物质中的带电粒子

我们可以从这些动作中推断出将两个物品摩擦在一起会导致它们带电吗？由于许多科学家的努力，在原子中发现了带电粒子。到 1900 年，确定原子是一种不可分割的粒子，其中至少包含一个亚原子粒子，即 JJ Thomson 发现的电子。 E. Goldstein 于 1886 年在气体放电中发现了新的辐射，远早于电子被发现，并将它们命名为运河射线。

这些射线是带正电的辐射，它们的发现导致了另一种亚原子粒子的发现。这个亚原子粒子的电荷量与电子相当，但符号相反。它的质量约为电子的 2000 倍。质子是给它的名字。通常，电子用字母 e- 表示，而质子用字母 p+ 表示。质子的质量是一个单位，它的电荷是一加一。一个电子的质量可以忽略不计，它的电荷是负电荷。

让我们尝试以下活动，以更好地了解物质中带电粒子的性质：

1. 如果你用塑料梳子梳理头发，然后将其放在小纸片附近，我们可以看到静电。梳子被拉到纸上。带电的梳子会在纸中产生相反的电荷，并且因为相反的电荷会吸引，所以纸会粘在梳子上。
2. 将气球与羊毛或合成毛衣摩擦后，将其放在墙壁或天花板上。气球被相反电荷的吸引力固定在适当的位置。

物质中的带电粒子

一个原子似乎是由平衡彼此电荷的质子和电子组成的。它还看起来质子在原子内部，因为虽然电子可以很容易地去除，但质子却不能。

A charged particle is a particle having an electric charge in physics. It might be an ion, such as a molecule or atom, having an excess or deficiency of electrons in comparison to protons. It may also be an electron, a proton, or another primary particle, all of which are thought to have the same charge (except antimatter). An atomic nucleus devoid of electrons, such as an alpha particle, might also be a charged particle.

亚原子粒子的发现

发现电子的存在和电荷

1897 年，一位名叫 JJ 汤普森的英国物理学家假设一个原子至少包含一个带负电的粒子。在进行实验时，他发现了电子。在实验过程中，气体在低压下通过玻璃排放管。

两个电极安装在玻璃放电管的两端，然后连接到高压源（电池）。接负极的电极称为阴极，接正极的电极称为阳极。

阴极发射出一股带负电的粒子流，汤姆森观察到了这一点。粒子流也向阳极移动。阴极射线是从放电管阴极端射出的带负电粒子流。他将其称为“微粒”，后来简称为“电子”。

质子的发现

卢瑟福在做著名的金箔实验时发现了质子。 1886 年，戈尔茨坦在用穿孔阴极进行实验时发现放电管中存在带正电的射线。该实验与 JJ Thomson 的实验相当，但情况不同。结果，从阳极放出带电粒子。

管射线是从放电管的阳极端发出的带正电的辐射。阳极射线和管射线被赋予射线。经过一系列实验后发现了质子。有助于原子带正电荷的粒子称为质子。

粒子的质量被发现是电子的 2000 倍。字母“p”用于象征质子。 1.6×10 ^-19库仑的正电荷是质子的绝对电荷。质子的质量为 1.6 × 10 ^-24 g，被认为是宇宙中最小的粒子之一（即氢原子的质量）。质子的质量被认为是一个单位，而它的电荷被认为是+1。

中子的发现

直到 1932 年才发现中子。詹姆斯查德威克通过使用散射粒子计算中性粒子的质量发现了它。原子核包含亚原子粒子“中子”。中子是一种中性粒子，用字母“n”表示。一个中子的质量为 1.6 × 10 ^-24克。

克是不足以计算这种微小的亚原子粒子的单位。因此，它们以道尔顿或 amu（原子质量单位）计算。质子和中子的共同质量约为 1 amu。

Name	Symbol	Charge	Relative Charge	Mass (kg)	Relative Mass
Electron	e-	-1.6 × 10-19 C	-1	9.1 * 10-31 kg	negligible
Proton	p+	1.6 × 10-19 C	+1	1.672 * 10-27 kg	1 u
Neutron	n	0	0	1.674 * 10-27 kg	1 u

亚原子粒子的发现引发了许多问题。其中之一是这些亚原子粒子在原子中的排列。结果，已经提出了这些带电粒子的各种模型。这些是原子结构这个巨大领域的基础。

示例问题

问题 1：写两个活动来了解物质中带电粒子的性质。

回答：

If you run a plastic comb through your hair and then position it near small pieces of paper, we can see static electricity. The comb is drawn to the paper. The charged comb causes an opposite charge in the paper, and because opposite charges attract, the paper adheres to the comb.

Placing a balloon against a wall or ceiling after rubbing it against a woollen or synthetic jumper. The balloon is held in place by the attraction of opposite charges.

问题2：电子是如何被发现的？

回答：

In the year 1897, a British physicist named J.J Thompson hypothesized that an atom contains at least one negatively charged particle. While working on an experiment, he discovered electrons. Gas was pushed through a glass discharged tube at low pressure during the experiment.

Two electrodes were installed at the glass discharge tube’s two opposite ends, which were then connected to a high voltage source (battery). The electrode that was connected to the negative end was known as the cathode, and the electrode that was connected to the positive end was known as the anode.

The cathode emitted a stream of negatively charged particles, which Thomson observed. The stream of particles was also moving towards the anode. Cathode rays are streams of negatively charged particles ejected from the discharge tube’s cathode end. He dubbed it “corpuscles,” which was later shortened to “electron.”

问题3：质子是如何被发现的？

回答：

Rutherford discovered proton while doing the famous gold foil experiment. In 1886, Goldstein discovered the presence of positively charged rays in a discharged tube while conducting an experiment with a perforated cathode. The experiment was comparable to J.J. Thomson’s, but the circumstances were different. As a result, charged particles were emitted from the anode.

Canal rays are the positively charged radiations emitted from the discharge tube’s anode end. Anode rays and canal rays were given to the rays. Protons were discovered after a series of experiments. The particles that contribute to the atom’s positive charge are known as protons.

The particles’ mass was discovered to be 2000 times greater than that of an electron. The letter “p” was used to symbolize protons. The positive charge of 1.6*10^-19 coulomb is the absolute charge of a proton. A proton has a mass of 1.6*10^-24 g and is regarded one of the smallest particles in the universe (which is mass of a hydrogen atom). A proton’s mass is regarded as one unit, while its charge is regarded as +1.

问题4：中子是如何被发现的？

回答：

It wasn’t until 1932 that the neutron was found. James Chadwick discovered it by calculating the mass of the neutral particle using scattered particles. The atom’s nucleus contains the subatomic particle “neutron.” Neutron is a neutral particle that is represented by the letter “n.” The mass of a neutron is 1.6 x 10^-24 grams.

Gram is an insufficient unit for calculating such minute subatomic particles. As a result, they are calculated in either Dalton or amu (atomic mass unit). A proton and a neutron have a mass of about 1 amu in common.

问题 5：给出亚原子粒子发现的简短时间表。

回答：

The presence of charged particles in an atom was discovered thanks to the efforts of many scientists. By 1900, it was established that the atom was an indivisible particle that contained at least one sub-atomic particle, the electron, which J.J. Thomson discovered. E. Goldstein discovered novel radiations in a gas discharge in 1886, long before the electron was detected, and named them canal rays.