A) r-process B) CNO Cycle C) triple- alpha process D) big bang nucleosynthesis
A) when the star has used up all its hydrogen fuel B) when the silicon fusion stops C) when the star has burned all its oxygen D) when the chromium fusion stops
A) Hydrogen fusion stops, and the pressure in the core decreases. B) Gravity squeezes the star until helium and hydrogen burning occur. C) Nuclear energy increases until carbon and helium burning occur D) Hydrogen fusion continues, and the pressure in the core increases.
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) 186 C) 111 D) 75
A) Zn-58 B) Ni-59 C) Cu-58 D) Ni-58
A) Henry Moseley B) Julius Lothar Meyer C) John Newlands D) Dmitri Mendeleev
A) At-210 B) Po-211 C) At-212 D) Rn-211
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) Primordial Nucleosynthesis B) R-Process C) Supernova Nucleosynthesis D) Stellar Nucleosynthesis
A) stable inner electrons B) valence electrons C) positron D) electrons in fully occupied orbitals
A) metallic bond B) ionic bond C) covalent bond D) electrostatic bond
A) CO2 B) IF5 C) I2 D) PF3
A) It has zero net dipole moment B) It is a polar molecule C) It has one ionic bond D) It has both polar and nonpolar covalent bonds
A) Se—Br B) Br—Br C) Na—Cl D) Li—Br
A) Polar bonds are arranged such that they cancel each other B) There is a polar bond present C) All bonds are polar covalent 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 polar B) Molecules of a substance is uniformly distributed in water solvent C) A molecule is water-fearing D) A molecule is water-loving
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 |