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Questions and Answers
An atom consists of a central nucleus of positive charge, around which negatively charged ______ revolve
electrons
The nucleus of an atom is made up of ______ which are positively charged, and neutrons which are electrically neutral
protons
Each element has a certain number of ______ and protons
electrons
An electron has a radius of about 10-15 meter and is more than twice as big as a ______
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An electron has a mass of about 9.11 x 10-28 grams. A proton is heavier than an electron (around 1840 times heavier than ______)
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A neutron has about the same mass as a ______
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The positive charge on each proton is equal in magnitude to the negative charge on each ______.
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An atom is electrically neutral in its stable state (number of ______ = number of protons).
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The outermost shell contains not more than 8 ______.
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The outermost shell determines the chemical valence and physical characteristics of an ______.
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The number of electrons in an incomplete outermost unfilled shell is called ______ electrons.
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Trivalent elements have three valence ______.
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Materials capable of having many free electrons and carrying electric current are called ______
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Materials which are only capable of having very few free electrons are called ______
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Materials which are capable of having not so many free electrons are called ______
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An atom or molecule that has become charged or electrically unbalanced is called an ______
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A positive ion is called a ______
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Electrons may leave a certain material through the process of ______
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