元素列表（来自百度百科）

备注：104~118号元素中部分元素，其汉字简体中文在部分设备上无法查看，故注明其繁体中文或以表意文字描述字符（IDS）描述的简体中文如下附表：

我是氢，我最轻，火箭靠我运卫星；

我是氦，我无赖，得失电子我最菜；

我是锂，密度低，遇水遇酸把泡起；

我是铍，耍赖皮，虽是金属难电离；

我是硼，黑银灰，论起电子我很穷；

我是碳，反应慢，既能成链又成环；

我是氮，我阻燃，加氢可以合成氨；

我是氧，不用想，离开我就憋得慌；

我是氟，最恶毒，抢个电子就满足；

我是氖，也不赖，通电红光放出来；

我是钠，脾气大，遇酸遇水就火大；

我是镁，最爱美，摄影烟花放光辉；

我是铝，常温里，浓硫酸里把澡洗；

我是硅，色黑灰，信息元件把我堆；

我是磷，害人精，剧毒列表有我名；

我是硫，来历久，沉淀金属最拿手；

我是氯，色黄绿，金属电子我抢去；

我是氩，活性差，霓虹紫光我来发；

我是钾，把火加，超氧化物来当家；

我是钙，身体爱，骨头牙齿我都在；

我是钛，过渡来，航天飞机我来盖；

我是铬，正六铬，酒精过来变绿色；

我是锰，价态多，七氧化物爆炸猛；

我是铁，用途广，不锈钢喊我叫爷；

我是铜，色紫红，投入硝酸气棕红；

我是砷，颜色深，三价元素夺你魂；

我是溴，挥发臭，液态非金我来秀；

我是铷，碱金属，沾水烟花钾不如；

我是碘，升华烟，遇到淀粉蓝点点；

我是铯，金黄色，入水爆炸容器破；

我是钨，高温度，其他金属早呜呼；

我是金，很稳定，扔进王水影无形；

我是汞，有剧毒，液态金属我为独；

我是铀，浓缩后，造原子弹我最牛；

我是镓，易融化，沸点很高难蒸发；

我是铟，软如金，轻微放射宜小心；

我是铊，能脱发，投毒出名看清华；

我是锗，可晶格，红外窗口能当壳；

我是硒，补人体，口服液中有玄机；

我是铅，能储电，子弹头里也有我。

Luminescence Is Cold Light

 Cold light is visible light produced by processes other than heating. Light sticks are an example of cold light, which is produced when chemicals are mixed together and the energy released is in the form of visible light.

The firefly in the photo gives off light that like the light stick is produced by a chemical reaction with visible light being the released energy.

Luminescence refers to any cold light. The term ‘luminescence’ was introduced in 1888 by Eilhard Wiedemann.

Luminescence can be caused by: chemical reactions, electrical energy, subatomic motions, or stress on a crystal.

Types of Luminescence

Bioluminescence, light emission by a living organism, such as fireflies.

Chemiluminescence, a result of a chemical reaction, such as glow sticks or luminol plus hemoglobin (chemical in blood). The glowing containers shown here contain mixtures of blood and luminol.

Electroluminescence: Light produced when an electric current is passed through a substance. An electroluminescent (EL) device is similar to a laser in that photons(units of light energy) are produced by the return of an excited electron to its ground state, but unlike lasers EL devices need much less energy to operate and do not produce coherent light. One kind of EL is an LED (light emitting diode), such as Christmas tree lights. LEDs present many advantages over incandescent light sources including lower energy consumption and longer lifetime.

Cathodoluminescence is an optical and electrical phenomenon whereby a beam of electrons is generated by an electron gun (e.g., cathode ray tube) and then impacts on a  luminescent material such as a phosphor, causing the material to emit visible light.

Mechanoluminescence is visible light emission resulting from any mechanical action on a solid. Examples are:

• Triboluminescence is an optical (visual) phenomenon in which visual light is generated when chemical bonds in a material are broken as a result of the material being pulled apart, ripped, scratched, crushed, or rubbed. Scientists do not fully understand this light producing process, but it is believed that the light results from the separation of electric charges leaving one side of the fracture positively charged and the other negatively charged. If the charge build up is great enough, an electric discharge across the gap occurs with the emission of light energy.
  Triboluminescence can be observed when breaking sugar crystals (especially Wint-O-Green Life Savers) and peeling adhesive tapes.

• Fractoluminescence and triboluminescence produce light in the same way. The difference is that fractoluminescence refers only to cold light produced by the fracturing of materials.

• Piezoluminescence is caused by pressure that results only in elastic deformation.
  Elastic deformation means the material can be stretched or twisted out of shape, but when the deforming pressure is removed, the material returns to its original shape. Thus, piezoluminescence differs from triboluminescence in that the material does not break.

• Sonoluminescence is the emission of short bursts of light from imploding bubbles in a liquid when excited by sound.

Photoluminescence, a result of absorption of photons  (units of radiant energy) by substances that are fluorescent or phosphorescent.

Fluorescence, is the emission  of photons (units of radiant energy) that are perceived as colors of light. This occurs as a result of high energy photons, such as Ultraviolet radiation (UV light) striking phosphors, which are chemicals that absorb high energy photons and emit lower energy photons (visible light).Note: Materials that fluoresce only do so during the time that the high energy radiant energy is being absorbed.

Examples of Fluorescence

1. The exoskeleton of scorpions contain phosphors. At night, scorpions can be located using a black light. The UV radiation emitted by this light causes the scorpion to fluoresce.

2.  See, Glo Germs for ideas for teaching kids proper hand washing as well as how germs can spread.

3. A Fluorescent Powder is Used to Represent Germs. This powder as well as a black light can be purchased from Educational Innovation online.

Phosphorescence, like fluorescence, is visible light emitted as excited electrons return to their normal positions called ground state. The difference being that the release of energy is slower for phosphorescence. While materials that fluoresce stop emitting light as soon as the exciting energy is removed, phosphorescent materials continue to glow for seconds to hours after the excitation energy is removed. Thus, these materials will glow-in-the-dark.

Phosphorescent Pigment can be purchased from
“Education Innovation” online. You will find information about phosphorescence and ideas for different experiments.

Fluorescence, phosphorescence, and photoluminescence occur when a sample is excited by absorbing photons and then emits them with a decay time that is characteristic of the sample environment. Fluorescence is a term used by chemists when the absorbing and emitting species is an atom or molecule. Phosphorescence is similar to fluorescence, except that the time between absorption and emission is much longer than in fluorescence. Photoluminescence is the term physicists use to describe the absorption and emission of light by things such as semiconductors and nanotubes. Regardless of the terminology, when samples absorb photons and then emit them at a different wavelength the resultant light can be dispersed by a spectrograph, the spectrum can be detected by a device such as a CCD, and information can be gleaned about the sample.

As illustrated in the diagram at right, fluorescence occurs when a chemical species absorbs a photon and is excited to a singlet electronic excited state, relaxes via non-radiative mechanisms, emits a lower-energy photon, and then transitions to the ground electronic state. In fluorescence, the time between absorption and emission is on the order of nanoseconds. The spectrum of the wavelengths emitted can be used to identify atoms and molecules, as well as to determine chemical structures. The intensity of the photons emitted can be used to determine the concentration of chemical species.

Since absorption is a requirement for the fluorescence process, molecules and functional groups that are strong UV-Vis absorbers can be strong fluorescers. For example, molecules with extended pi-electron systems, including aromatic and conjugated aromatic rings, make excellent fluorescers (known as fluorophores). In biology, fluorophores are attached to molecules such as proteins, are excited, and the resultant fluorescence used to image molecules and cells. Spectral analysis of this fluorescence can give chemical information about biological systems.

Phosphorescence
Phosphorescence is similar to fluorescence except the time between photon absorption and emission is from seconds to hours rather than nanoseconds. Like fluorescence, phosphorescence begins with absorption by a photon and excitation to a singlet electronic state. Via a process called intersystem crossing, the singlet state couples to a triplet electronic excited state, which then gives off a photon and relaxes to the ground electronic state. Singlet-triplet coupling is “forbidden” (which is responsible for the time delay in phosphorescence compared to fluorescence). The amino acid tryptophan phosphoresces, so phosphorescence can be used to study proteins.

Photoluminescence
Photoluminescence is fluorescence as applied to semiconductors and other materials. Dispersing the photoluminescent light to form a spectrum can give information such as the purity of semiconductors and the structure of nanotubes.