Corresponding to the sun in the solar system is the nucleus of the atom.
举一反三
- Which of the following is not a valid conclusion from Rutherford’s alpha particle scattering experiment? ( ) A: The nucleus must be positively charged B: The nucleus must be very small compared to the atom C: The atom is mainly empty space D: The mass of the atom is mostly concentrated in the nucleus
- Around the nucleus of a hydrogen atom moves a single electron._
- According to Newton's principle ______. A: the force of gravity keeps planets orbiting around the sun rather than flying off B: the sun is the most massive object, making up 99.8 percent of the mass of the solar system C: the amount of mass determine how fast the objects travel as they orbit each other D: Pluto receives the least force of gravity from the sun of all the planets in the solar system
- The atomic weight of an atom, or the molecular weight of a molecule, is its mass relative to that of a(n) ________ atom. This is essentially equal to the number of protons plus neutrons that the atom or molecule contains.
- A sidereal day is shorter than a solar day. This difference is due to（）. A: irregularities in the daily rotational rate of the Sun B: the space motion of the solar system C: the precession of the equinoxes D: the use of different reference point