Explain why the number of protons in an atom must always equal the number of electrons.

Which best describes how johannes kepler developed his laws of planetary motion

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.

An alkaline battery produces electrical energy according to the following equation. zn(s) + 2 mno2(s) + h2o(l) zn(oh)2(s) + mn2o3(s) (a) determine the limiting reactant if 17.5 g zn and 31.0 g mno2 are used. (type your answer using the format ch4 for ch4.) (b) determine the mass of zn(oh)2 produced. _ g