Physical Science Chapter 3 – Flashcards
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Which statement is true according to Dalton's theory?
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Atoms of the same element are exactly alike.
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Which statement about the atomic nucleus is correct?
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The nucleus is made of protons and neutrons and has a positive charge.
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The charge of an electron
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-1
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Atoms have no electric charge because
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have an equal number of protons and electrons
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Bohr's model
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planets orbiting the sun
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modern atomic theory, nearly impossible to determine
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position
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order of elements based on
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the number of protons in the nucleus
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atoms of elements in same group have same number of
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valence electrons
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ionization
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losing or gaining electrons
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oxygen atomic number 8, this means
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eight protons in its nucleus
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mass number equals
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protons plus the number of neutrons
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atomic mass unit
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one twelfth the mass of a carbon-12 atom
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alkali metals
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located in the left-most column
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alkali metals extremely reactive because
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have 1 valence electron that is easily removed to form a positive ion
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noble gases
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exist as single atoms rather than as molecules
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semiconductors
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can conduct heat and electricity under ceratin conditions
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halogens
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gaining an electron to form a negative ion
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carbon and other nonmetals
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on the right side
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mole describes
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amount of a substance
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atomic mass of carbon is 12 amu, 1 mole of pure carbon
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12 g
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Avogadro's constant is defined as number of particles in
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one mole of a pure substance
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molar mass
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the mass in grams of 1 mole of a substance
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average atomic mass of potassium is 39 amu, what is the mass of 2.0 mol
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78 g
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6.50 mol
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338 g
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85.5 g
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4.5 mol
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atom comes
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divided
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1st person suggest
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Democritus
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nucleus _______ charge
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positive
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neutrons and protons found
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nucleus
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order of elements
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protons
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isotopes have same _______; different _________
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number;masses
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atom of potassium ____ neutrons
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20
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lightest hydrogen isotope
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Protium
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atoms of alkaline-earth
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two
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located in center
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transition metals
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highly reactive
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halogens
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molar mass of krypton
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419
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nitrogen
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2.8
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palladium
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0.500
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Explain
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Atoms have an equal number of protons, which each have a charge of +1, and electrons, which each have a charge of -1. The positive and negative charges cancel.
