A) big bang nucleosynthesis B) CNO Cycle C) r-process D) triple- alpha process
A) when the star has used up all its hydrogen fuel B) when the star has burned all its oxygen 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) Gravity squeezes the star until helium and hydrogen burning occur. D) Hydrogen fusion continues, and the pressure in the core increases.
A) Stellar formation and evolution formed their elements from Be to Fe. B) Stellar evolution formed no elements at all. 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) 111 B) 75 C) 261 D) 186
A) Zn-58 B) Ni-59 C) Cu-58 D) Ni-58
A) John Newlands B) Henry Moseley C) Julius Lothar Meyer D) Dmitri Mendeleev
A) Po-211 B) At-210 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) All of these C) Atomic number is the number of neutrons, the atoms are arranged by the increasing number of protons D) Atomic number is the number of electrons, the atoms are arranged by the decreasing number of protons
A) R-Process B) Primordial Nucleosynthesis C) Supernova Nucleosynthesis D) Stellar Nucleosynthesis
A) positron B) valence electrons C) stable inner electrons D) electrons in fully occupied orbitals
A) covalent bond B) ionic bond C) metallic bond D) electrostatic bond
A) IF5 B) I2 C) CO2 D) PF3
A) It has both polar and nonpolar covalent bonds B) It has zero net dipole moment C) It has one ionic bond D) It is a polar molecule
A) Br—Br B) Na—Cl C) Se—Br D) Li—Br
A) There is a polar bond present B) Polar bonds are arranged such that they cancel each other 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 make the other substance polar B) To produce an aromatic solution C) To bridge the difference in polarity of two or more substances D) To speed up the chemical reaction without being consumed in the process
A) A molecule is water-fearing B) Molecules of a substance is uniformly distributed in water solvent C) A molecule is water-loving D) A molecule is polar
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 |