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