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What's the term for one-twelfth the mass of a carbon-12 atom?
atomic mass unit
What's the term for a subatomic particle with no charge?
neutron
Who first suggested that atoms exist?
Democritus
What's the term for the weighted average of the masses of the isotopes of an element?
atomic mass
What's the term for atoms with the same number of protons, but different numbers of neutrons?
isotopes
Who said that atoms retain their identity during a chemical reaction?
Dalton
What's the term for the smallest particle of an element that retains the properties of that element?
atom
What's the term for the central part of an atom that is made of the protons and neutrons?
nucleus
What's the term for the total number of protons and neutrons in the nucleus of an atom?
mass number
Who discovered the amount of charge on an electron?
Millikan
What did Dalton say about atoms of the same element?
They are identical.
What's the term for a negatively charged subatomic particle?
electron
Which particle has a relative mass that is 1/1840 of the mass of a hydrogen atom?
electron
What's the term for a positively charged subatomic particle?
proton
Who said that atoms contain electrons?
JJ Thomson
What's the term for the number of protons in the nucleus of an element?
atomic number
Who discovered the neutron?
Chadwick
Identify one change to Dalton's atomic theory as new evidence was collected.
atoms of the same element are not identical and atoms are divisible
Why did Thomson reason that all atoms contain electrons?
charge-to-mass ratio did not change when the gas in the tube or the metal in the electrodes changed
What do we know about the number of protons and electrons in a neutral atom?
They are equal
Which subatomic particles are found in the nucleus?
protons and neutrons
Who's atomic model was known to be true?
Rutherford's
If an element has the atomic number 46, how many protons and electrons does it contain?
46 protons and 46 electrons
What does the number in oxygen-16 represent?
mass number
Atoms of the same element have the same number of which particle?
protons
Isotopes of the same element have different numbers of which particle?
neutrons
Use your periodic table to write the symbol, number of protons, and number of electrons in a platinum atom.
Pt, 78 protons, 78 electrons
Use the periodic table to determine the umber of neutrons in uranium-235.
235-92 = 143
If an atom has the atomic number 60 and mass number 146, how many protons, electrons, and neutrons does it contain?
60 protons, 60 electrons, 86 neutrons
If give the nuclear symbols for several elements, how could you tell if the atoms were isotopes?
same bottom number, different top number