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