Chapter 4 chemistry study guide – Flashcards
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Democritus
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Reasoned that atoms were indivisible and indestructible.
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Atom
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The smallest particle of an element that retains its identity in a chemical reaction.
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Dalton
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Transformed Democritus ideas on atoms into a scientific theory.
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Dalton's Atomic Theory 1.
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All elements are composed of tiny indivisible particles
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Dalton's atomic theory 2.
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Atoms of the same element are identical. The atoms of any one element are different from those of another.
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Dalton's atomic theory 3.
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Atoms of different elements can physically mix together or can chemically combine in simple whole number ratios to form compounds
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Dalton's atomic theory 4.
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Chemical reactions occur when elements are separated from each other, joined, or rearranged in a different combination.
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Electrons
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Negatively charged subatomic particles
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Cathode Ray
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Experiment performed by Thomson. One electrode became positively charged, one became negative. The result was a glowing beam.
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Robert A. Millikan
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Carried out experiments to find the quantity of an electrons charge. Oil drop experiment.
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Electron charge
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One unit of negative charge
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Electrons mass
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1/1840
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Electron charge
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1-
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Proton charge
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1+
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Protons
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Subatomic positively charged
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Neutron
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Subatomic negatively charged
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Thomson discovery
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The electrons
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Thomson model
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Plum pudding model
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Rutherford
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Good foil experiment
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Nucleus
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Tiny central core of an atom and is composed of protons and electrons
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Nuclear atom
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Has a positively charged nucleus. Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
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Elements are different
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They all contain a different number of protons
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Atomic number
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The number of protons in that element.
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Mass number
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The total number of protons and neutrons
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Isotopes
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Atoms that have the same number of protons but different numbers of neutrons.
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Isotopes difference
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They have different mass numbers because they have a different number of neutrons.
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Atomic mass unit (amu)
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1/12 of the mass of a carbon atom
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Atomic mass
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Weighted average mass of the atoms naturally occurring sample of the element.
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Calculating atomic mass
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Mass of each isotope x natural abundance, and then add the products.
