element (redirected from chemical element)

element /el·e·ment/ (el´ĕ-ment)

1. any of the primary parts or constituents of a thing.

2. in chemistry, a simple substance that cannot be decomposed by chemical means and that is made up of atoms which are alike in their peripheral electronic configurations and so in their chemical properties and also in the number of protons in their nuclei, but which may differ in the number of neutrons in their nuclei and so in their mass number and in their radioactive properties.

3. in the philosophies underlying some complementary medicine systems, a member of a group of basic substances that give rise to everything that exists.

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five elements 

1. see under phase.

2. in ayurvedic tradition, the basic entities (earth, air, fire, water, and space) whose interaction gives rise to material existence.

formed elements of the blood  the blood cells.

trace elements  chemical elements distributed throughout the tissues in very small amounts and that are either essential in nutrition, as cobalt, copper, etc., or harmful, as selenium.

transposable element  see transposon.

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el·e·ment (l-mnt)

n.

1. A substance that cannot be reduced to simpler substances by normal chemical means and that is composed of atoms having an identical number of protons in each nucleus.

2. A fundamental, essential, or irreducible constituent of a composite entity.

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element

Etymology: L, elementum, first principle

one of more than 100 primary, simple substances that cannot be broken down by chemical means into any other substance. Each atom of any element contains a specific number of protons in the nucleus and an equal number of electrons outside the nucleus. In most elements, the nucleus may contain a variable number (high or low) of neutrons. An element with a disproportionate number of neutrons may be unstable, in which case the nucleus undergoes radioactive decay into a more stable element. See also atom, compound, molecule, radioactivity.

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element [el´ĕ-ment]

1. any of the primary parts or constituents of a thing.

2. in chemistry, a simple substance that cannot be decomposed by ordinary chemical means; elements are the basic components of which all matter is composed.

Chemical elements are made up of atoms, each of which consists of a nucleus with a cloud of negatively charged electrons revolving around it. The two major components of the nucleus are protons and neutrons. The number of protons in the atoms of a particular element is always the same, and therefore the physical and chemical properties of the element are always the same. It is possible, however, for a chemical element to exist in several different forms, the difference depending on the number of neutrons in the nucleus of its atoms. Different forms of the same element are called isotopes.

There are at least 105 different chemical elements known. (See Appendix 6 for a list of the elements, and the symbol, atomic weight, and atomic number of each.) The atomic number of an element is determined by the number of protons in the nucleus of one of its atoms. The mass number of an isotope is determined by the total number of neutrons and protons in the nucleus.

Stable Chemical Elements. A stable chemical element is one that contains an optimal ratio or range of ratios between the number of protons and neutrons in the nucleus. A stable element does not spontaneously transmute into another element and therefore does not give off radiation. The stable elements are those that have an atomic number below 84, except for a few, such as potassium and rubidium, which are weakly radioactive.

Radioactive Chemical Elements. A radioactive chemical element does not contain an optimal proton-to-neutron ratio in its atomic nuclei and therefore readily gives off nuclear particles until all nuclei have attained the optimal combination of protons and neutrons. The spontaneous releasing of its nuclear particles changes the radioactive atom into a new atom (transmutation).ƒ

As radioactive elements disintegrate and form new chemical elements, a tremendous amount of energy is released. This emission of energy and nuclear particles is called radiation. The radiations may be electrically charged particles having size and mass, such as alpha particles and beta particles, or they may be nonparticulate and contain no electrical charges, such as gamma rays. Most radioactive elements give off either alpha or beta particles and at the same time emit gamma radiation.

formed e's of the blood the blood cells.

trace element a chemical element present or needed in extremely small amounts by plants and animals; such elements include manganese, copper, cobalt, zinc, and iron.

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element,

n any substance that cannot be reduced into a less complex substance, all atoms of which are defined as having the same number of protons.

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element,

n a simple substance that cannot be decomposed by chemical means and is made up of atoms that are alike in their peripheral electronic configuration and chemical properties but differ in their nuclei, atomic weights, and radioactive properties.

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element

1. any of the primary parts or constituents of a thing.

2. in chemistry, a simple substance that cannot be decomposed by ordinary chemical means; the basic 'stuff' of which all matter is composed.

Chemical elements are made up of atoms. Each atom consists of a nucleus with a cloud of negatively charged particles (electrons) revolving around it. The two major components of the nucleus are protons and neutrons. The number of protons in the atoms of a particular element is always the same, and therefore the physical and chemical properties of the element are always the same. It is possible, however, for a chemical element to exist in several different forms, the difference depending on the number of neutrons in the nucleus of its atoms. Different forms of the same element are called isotopes.

There are at least 105 different chemical elements known. Table 6 lists the elements, and the symbol, atomic weight and atomic number of each. The atomic number of an element is determined by the number of protons in the nucleus of an atom of the element. The mass number of an isotope is determined by the total number of neutrons and protons in the nucleus.

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formed e's (of the blood)

erythrocytes, leukocytes and platelets.

element points

see horary points.

trace element

a chemical element present or needed in extremely small amount by plants and animals, such as manganese, copper, cobalt, zinc, iron. See also trace element.

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Patient discussion about element.

Q. what consider to be a good nutrition for children? does it has to include some specific nutrition elements?

A. there's many things you should consider about children's nutrition, the amount of books written about kids nutrition can fill a library...
vitamins, organic vs industrial, fast food vs home made etc.
here are 2 video libraries that i'm sure you'll find all the info you seek in them-

http://www.thedoctorsvideos.com/categories/26/Nutrition

http://www.drmdk.com/html/nutrition.html