15 what subatomic particle was discovered in the

15) What subatomic particle was discovered in the cathode ray tube experiment?
a) proton b) electron c) neutron d) gravitron
Short Answer
16) In 1909, a team of British scientists led by Ernest Rutherford, carried out the Gold Foil Experiment to determine
the arrangement of particles in the atom. In this experiment, alpha particles were used to bombard gold foil.
a) Most of the alpha particles passed through the gold foil undeflected. What conclusion was made
about the structure of the atom based on this observation? (1 pt.)
b) A few of the alpha particles were deflected back at the source and toward the screen. What did
this observation reveal about the structure of the atom? (1 pt.)
17) An element has two isotopes. 90% of the isotopes have a mass number of 20 amu, while 10% have a
mass number of 22 amu. Calculate the atomic mass of the element. Show all work with units. (3 pts.)
18) Complete the chart below: (9 pts.)
Substance Atom or Ion? # protons # neutrons # electrons Atomic # Mass number
Mg
+2
Rb
Cl
-

Answer Key
17. 20.2 amu
18.
Substance Atom or Ion? # protons # neutrons # electrons Atomic # Mass number
Mg
+2
Ion 12 12 10 12 24
Rb Atom 37 48 37 37 85
Cl
-
Ion 17 18 18 17 35