The second period of the periodic table is composed of ______________ (how many?) elements
Fill in the blank(s) with correct word
8
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Size of the Nucleus: A proton is projected at a stationary 
Ra aluminum target. The proton momentarily comes to a halt at a distance from the center of an aluminum nucleus, equal to twice the nuclear radius. Assume that the nucleus retains its spherical shape and that the nuclear force on the proton is negligible. The initial kinetic energy of the proton, in MeV, is closest to:
A. 8.7 MeV. B. 5.8 MeV. C. 2.9 MeV. D. 13 MeV. E. 17 MeV.
If total internal reflection occurs at a glass-air surface:
a. no light is reflected. b. no light is refracted. c. light is leaving the air and hitting the glass with an incident angle less than the critical angle. d. light is leaving the air and hitting the glass with an incident angle greater than the critical angle.
What's an isotope?
a. a radioactive material b. an atom of an element with a different number of neutrons in the nucleus c. an electrically charged atom d. none of the above
A 1000-kg car is moving at 30.0 m/s around a horizontal curve whose radius is 100 m. What is the magnitude of the frictional force required to keep the car from sliding?
A) 9000 N B) 9810 N C) 300 N D) 900 N E) 3000 N