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