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CHEMICAL CHANGES

CHEMICAL CHANGES. By : Fidel Maldonado. DEMOCRITUS.

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CHEMICAL CHANGES

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  1. CHEMICAL CHANGES By : Fidel Maldonado

  2. DEMOCRITUS • The Democritus Atomic Theory revolves around the atoms that are present in the atmosphere. These are about the atoms that are present in all the forms of existence; for instance, solid or liquid. The theory states that these atoms are all individually created and cannot be separated, no matter what scientific procedures are applied.

  3. JOHN DALTON • 1) All matter is made of atoms. Atoms are indivisible and indestructible. • 2) All atoms of a given element are identical in mass and properties • 3) Compounds are formed by a combination of two or more different kinds of atoms. • 4) A chemical reaction is a rearrangement of atoms.

  4. ERNEST.RUTHERFORD • In 1911 in England, physicists Ernest Rutherford(1871-1937),Hans Geiger (1882-1945) and Ernest Marsden (1889-1970) used high-speed lightweight atoms called alpha particles (generated by radioactive material) to bombard very thin pieces of gold foil.

  5. NEILS BOHR He used information about the nature of the emission of light by heated objects to update Rutherfords model. He described electrons as moving around the nucleus in fixed orbits that have a set amount of energy.

  6. JOHN THOMSON • He had conducted many experiments.from these experiments Thomas identified the electron which carries a negative charge.Thomson knew that atoms were electrically neutral.so he proposed that theatom was a postive sphere with negative electrons embedded in it lik raisins in a roll or bun.

  7. NEUCLEUS • The diameter of the nucleus is in the range of 1.75 fm (femtometre) (1.75×10−15 m)

  8. MOLECULES • A molecule is an electrically neutral group of two or more atoms held together by covalent chemical bonds.

  9. MASS NUMBER • The mass number, also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus.

  10. ISOTOPE Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons.

  11. SUBATOMIC PARTICLES • are the smaller particles composing nucleons and atoms. There are two types of subatomic particles: elementary particles, which are not made of other particles, and composite particles. Particle physics and nuclear physics study these particles and how they interact.

  12. SPECTOGRAPH • A spectrograph is an instrument that separates an incoming wave into a frequency spectrum. There are several kinds of machines referred to as spectrographs, depending on the precise nature of the waves

  13. a table illustrating the periodic system, in which the chemical elements, formerly arranged in the order of their atomic weights and now according to their atomic numbers, are shown in related groups.

  14. CHEMICAL SYMBOL • A chemical symbol is a 1- or 2-letter internationally agreed code for a chemical element, usually derived from the name of the element

  15. ATOMIC NUMBER • In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus

  16. NOBLE GASSES • The noble gases are a group of chemical elements with very similar properties: under standard conditions, they are all odorless, colorless, monatomic gases, with very low chemical reactivity.

  17. ELECTRON SHELLS • An electron shell may be thought of as an orbit followed by electrons around an atom's nucleus.

  18. NEUTRAL ATOM • A neutral atom is an atom that has an equal number of electrons and protons in it. Protons have a +1 charge while electrons have a -1 charge. In a neutral atom these equal out.

  19. REACTIVITY • the relative capacity of an atom, molecule, or radical to undergo a chemical reaction with another atom, molecule, or compound. • Physics . a measure of the deviation from the condition at which a nuclear reactor is critical.

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