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