Central subatomic particles

The internal structure of the atom, that is, how the subatomic particles are arranged in space within the atom, is very complicated. All the protons, plus varying numbers of electrically neutral particles called neutrons, cluster inside the central nucleus. The 1... 

Determine the arrangement and structure of subatomic particles in atoms. Protons, neutrons, and electrons play a central role in everything chemistry, and you find their most basic properties in this part. 

Atoms themselves are made up of even smaller particles. These subatomic particles are protons, neutrons, and electrons. Protons and neutrons cluster together to form the central core, or nucleus, of an atom. Fast-moving electrons occupy the space that surrounds the nucleus of the atom. As their names imply, subatomic particles are associated with electrical charges. Table 2.1 and Figure 2.2 summarize the general features and properties of an atom and its three subatomic particles. 

Figure 12-1. Tb shows the sensor head from the Mars rover missions of 2(K)4. The head contains a curium-244 source that emits X-rays and 5.81 MeV alpha particles. The X-rays cause fluorescence in Martian rock samples, and the alpha particles stimulate X-ray emission as well. X-ray emission stimulated by bombardment by alpha and other subatomic particles such as protons is called punicle induced X-ru emission, or I lXE. llie X-ray detector is a new room-temperature type, which in the low temperature of the Martian night (below 4U°C.) exhibits low noise and high signal-to noise ratio for excellent resolution and sensitivity. Note the concentric design of the sensor head with six (im-244 sources arranged around the central detector. The X-ray spectrum of Figure 12-14 was acquired with the sensor head.

In 1903, Marie Curie, her husband and Henri Becquerel received the Nobel Prize in physics Marie won another Nobel prize (chemistry) in 1911. In 1900, Max Planck had postulated that light energy must be emitted and absorbed in discrete particles, called quanta. In Paris in 1924, Victor de Broglie concluded that if light could act as if it were a stream of particles, particles could have the properties of waves. Both quanta and waves are central to quantum physics. Quantum theory states that energy comes in discrete packets, called quanta, which travel in waves. The principle of wave-particle duality states that all subatomic particles can be considered as either waves or particles. Light is a stream of photon particles that travel in waves. 

Protons Positively charged subatomic particles found in the nucleus Neutrons Electrically neutral subatomic particles found in the nucleus Nucleus Small central core of the atom contains the protons and neutrons... 

The last column in Table 3-1 lists the location of the three subatomic particles. Protons and neutrons are located in the nucleus, a dense central core in the middle of the atom, while the electrons are located outside the nucleus (see Where Are Those Electrons later in this chapter). 

The systematic introduction of light, energy, and subatomic particles aids in student appreciation of the central ideas of atomic theory and the periodic table of the elements. 

Nucleus Chemically, the central part of an atom, containing protons, neutrons and a variety of other subatomic particles. Biologically, the subcellular organelle which contains the genetic information, as DNA, arranged in chromosomes. 

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