A) CNO Cycle B) r-process C) big bang nucleosynthesis D) triple- alpha process
A) when the chromium fusion stops B) when the star has burned all its oxygen C) when the silicon fusion stops D) when the star has used up all its hydrogen fuel
A) Hydrogen fusion stops, and the pressure in the core decreases. B) Gravity squeezes the star until helium and hydrogen burning occur. C) Hydrogen fusion continues, and the pressure in the core increases. D) Nuclear energy increases until carbon and helium burning occur
A) Stellar formation and evolution formed their elements from Be to Fe. B) Stellar explosion, or supernova, formed the elements heavier the Fe. C) Stellar evolution formed no elements at all. D) The big bang nucleosynthesis formed the light elements (H, He, and Li).
A) 186 B) 111 C) 75 D) 261
A) Zn-58 B) Ni-58 C) Cu-58 D) Ni-59
A) Julius Lothar Meyer B) Henry Moseley C) John Newlands D) Dmitri Mendeleev
A) Po-211 B) At-212 C) At-210 D) Rn-211
A) Atomic number is the number of neutrons, the atoms are arranged by the increasing number of protons B) Atomic number is the number of protons, the atoms are arranged by the increasing number of protons C) Atomic number is the number of electrons, the atoms are arranged by the decreasing number of protons D) All of these
A) Stellar Nucleosynthesis B) Primordial Nucleosynthesis C) R-Process D) Supernova Nucleosynthesis
A) valence electrons B) positron C) electrons in fully occupied orbitals D) stable inner electrons
A) ionic bond B) covalent bond C) metallic bond D) electrostatic bond
A) CO2 B) I2 C) IF5 D) PF3
A) It is a polar molecule B) It has zero net dipole moment C) It has both polar and nonpolar covalent bonds D) It has one ionic bond
A) Na—Cl B) Br—Br C) Se—Br D) Li—Br
A) All bonds are polar covalent B) There is a polar bond present C) Polar bonds are arranged such that they cancel each other D) There is lone pair in the central atom and arranged unevenly that cause the dipole moment
A) To speed up the chemical reaction without being consumed in the process B) To bridge the difference in polarity of two or more substances C) To make the other substance polar D) To produce an aromatic solution
A) A molecule is water-loving B) Molecules of a substance is uniformly distributed in water solvent C) A molecule is polar D) A molecule is water-fearing
A) The water molecule is neutral. B) The unequal sharing of electrons gives the water molecule a slight negative charge near its hydrogen atoms and a slight positive charge near its oxygen atom C) The equal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms D) The molecule has two poles, at which it is colder than other regions of the molecule. |