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