The half-life of radioactive Atoms Refers to A. The time required for half the Atoms in a sample to the decay.

B. The number of atoms in a sample that are radioactive.

C. Half the time required for all the Atoms in a sample to disintegrate.

D. The number of atoms that decay in half a second.

NO LINKS

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.

Lab reagent, hypothesis test.a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl.these six measurements are assumed to be an srs of all possible measurements from solution.they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution.carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?