Test CH 4

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Democritus believed that atoms were indivisible and indestructible

Three types of subatomic particles are electrons, protons, and neutrons.

The number of neutrons is an atoms is the difference between the mass number and atomic.

The periodic table lets you easily compare the properties of one element.

Rutherford = Gold foil experiment

Millikin = Oil drop

J.J Thompson = discovered the electron

Ions= an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Isotope=each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.

How are Ions and Isotopes diff? An ion is an atom with a net electric charge due to the loss or gain of one or more electrons. An isotope is each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei

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The chemical symbol is the big letter or two letters given.

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Atomic number is the number above the Chemical symbol

The mass number is the number below the chemical symbol

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Subatomic Particles

How to find the # of each given element,ion,isotope, etc. =Atoms are electrically neutral; the positive and negative charges are equal.

Locate the atomic number of a given element on the periodic table; this is the number of protons found in the nucleus. It is usually listed above the element symbol. The identity of an element is based upon the number of protons found in the nucleus.

Determine the number of electrons using the atomic number. An atom has a neutral charge, so the positive and negative charges are equal to each other. The atomic number is also the number of electrons.

an atom is neutral, the number of electrons is equal to the number of protons. Electrons circle the nucleus, which is made up of protons and neutrons.

mass number: The total number of protons and neutrons in an atomic nucleus.

The atomic mass reported on a periodic table is the weighted average of all the naturally occurring isotopes. Being an average it would be most unlikely to be a whole number.

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Dalton’s atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.

Dalton’s atomic theory also stated that all compounds were composed of combinations of these atoms in defined ratios.

Dalton also postulated that chemical reactions resulted in the rearrangement of the reacting atoms.