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