Atomic Scientists
Which ancient thinker proposed that matter consists of tiny particles called atomos?
Democritus
Which experiment led to the discovery of the electron?
Cathode-ray
Which subatomic particle has a positive charge
Proton
A neutral atom has 18 protons, mass of 40 amu, and 22 neutrons. How many electrons will it have?
18
Write 6.5% as a decimal for an atomic-mass calculation.
0.065
Who developed the first modern atomic theory using evidence from chemical reactions?
John Dalton
What analogy describes Thomson's model of the atom?
Plum Pudding
Which subatomic particle has the smallest mass
Electron
An atom has 15 protons, 15 electrons and 16 neutrons. What is its mass number?
31
The average atomic mass is usually closest to which isotope?
The most abundant
Who discovered the electron using a cathode-ray tube?
JJ Thomson
What experiment involved firing alpha particles at a thin sheet of gold?
Gold-foil Experiment
Which particle(s) can be changed and still be the same element?
Electrons and Neutrons
An isotope has a mass number of 65 and an atomic number of 29. It also has 29 electrons. How many neutrons will it have?
36
An element is 75% isotope-10 and 25% isotope-12. What is its average atomic mass with label?
10.5 amu
Who determined the charge and mass of an electron with his oil drop experiment?
What did Rutherford conclude when most alpha partciles passed through the gold foil?
Atom is mostly empty space
What is it called when we change the number of neutrons in a nucleus?
Isotope
A sample of Skittlium contains 29 atoms of the Gummy isotope, 14 atoms of the Freeze-dried isotope, and 32 atoms of the Original isotope. What is the percent abundance of the Gummy isotope to 1 decimal?
38.7%
Who discovered the neutron?
James Chadwick
What caused a few particles to be strongly deflected in Rutherford's experiment?
Positive nucleus
What is the relative atomic mass of an electron in relation to the proton?
1/1840 amu
Write the nuclear notation for Sodium-23 which has 11 electrons in a neutral state.
2311Na
Calculate the atomic mass of iodine to 1 decimal place. The two isotopes of bromine have atomic masses and relative abundance of 125.8 amu (50.69%) and 127.4 (49.31%).
126.6 amu