A) CNO Cycle B) r-process C) triple- alpha process D) big bang nucleosynthesis
A) when the star has used up all its hydrogen fuel B) when the chromium fusion stops C) when the star has burned all its oxygen D) when the silicon fusion stops
A) Gravity squeezes the star until helium and hydrogen burning occur. B) Hydrogen fusion continues, and the pressure in the core increases. C) Hydrogen fusion stops, and the pressure in the core decreases. D) Nuclear energy increases until carbon and helium burning occur
A) Stellar explosion, or supernova, formed the elements heavier the Fe. B) Stellar formation and evolution formed their elements from Be to 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) 75 C) 261 D) 111
A) Ni-59 B) Zn-58 C) Cu-58 D) Ni-58
A) Dmitri Mendeleev B) Julius Lothar Meyer C) Henry Moseley D) John Newlands
A) At-210 B) Rn-211 C) At-212 D) Po-211
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 electrons, the atoms are arranged by the decreasing 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) Stellar Nucleosynthesis B) Supernova Nucleosynthesis C) Primordial Nucleosynthesis D) R-Process
A) positron B) stable inner electrons C) electrons in fully occupied orbitals D) valence electrons
A) electrostatic bond B) metallic bond C) ionic bond D) covalent bond
A) PF3 B) CO2 C) IF5 D) I2
A) It has one ionic bond B) It has zero net dipole moment C) It has both polar and nonpolar covalent bonds D) It is a polar molecule
A) Se—Br B) Br—Br C) Li—Br D) Na—Cl
A) Polar bonds are arranged such that they cancel each other B) There is lone pair in the central atom and arranged unevenly that cause the dipole moment C) All bonds are polar covalent D) There is a polar bond present
A) To make the other substance polar B) To speed up the chemical reaction without being consumed in the process C) To produce an aromatic solution D) To bridge the difference in polarity of two or more substances
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 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 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 molecule has two poles, at which it is colder than other regions of the molecule. D) The water molecule is neutral. |