A) triple- alpha process B) CNO Cycle C) big bang nucleosynthesis D) r-process
A) when the chromium fusion stops B) when the silicon fusion stops C) when the star has used up all its hydrogen fuel D) when the star has burned all its oxygen
A) Gravity squeezes the star until helium and hydrogen burning occur. B) Nuclear energy increases until carbon and helium burning occur C) Hydrogen fusion stops, and the pressure in the core decreases. D) Hydrogen fusion continues, and the pressure in the core increases.
A) Stellar explosion, or supernova, formed the elements heavier the Fe. B) The big bang nucleosynthesis formed the light elements (H, He, and Li). C) Stellar evolution formed no elements at all. D) Stellar formation and evolution formed their elements from Be to Fe.
A) 186 B) 111 C) 75 D) 261
A) Cu-58 B) Ni-58 C) Zn-58 D) Ni-59
A) John Newlands B) Julius Lothar Meyer C) Henry Moseley D) Dmitri Mendeleev
A) Po-211 B) At-212 C) At-210 D) Rn-211
A) Atomic number is the number of electrons, the atoms are arranged by the decreasing number of protons B) Atomic number is the number of protons, the atoms are arranged by the increasing number of protons C) All of these D) Atomic number is the number of neutrons, the atoms are arranged by the increasing number of protons
A) Primordial Nucleosynthesis B) Stellar 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) electrostatic bond C) metallic bond D) covalent bond
A) IF5 B) CO2 C) PF3 D) I2
A) It has one ionic bond B) It has both polar and nonpolar covalent bonds C) It is a polar molecule D) It has zero net dipole moment
A) Se—Br B) Li—Br C) Na—Cl D) Br—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 produce an aromatic solution C) To bridge the difference in polarity of two or more substances D) To make the other substance polar
A) Molecules of a substance is uniformly distributed in water solvent B) A molecule is water-fearing C) A molecule is water-loving D) A molecule is polar
A) The molecule has two poles, at which it is colder than other regions of the molecule. B) 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 C) The water molecule is neutral. D) 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 |