40. Look at the periodic table. Barium has 2 valence electrons. So to become stable it needs to have a total of 8 valence electrons. So choice 2 (2 chlorine atoms) is the only reasonable answer. Chlorine has 7 valence electrons and Barium has 2 valence electrons. In order to get a stable number of electrons there has to be two chlorine atoms. Barium will share one valence electron with 7 chlorine valence electrons. The other Barium valence electron will be shared with 7 chlorine valence electrons.

41. Look at Table T and you will find that K= (degrees Celsius) C - 273. Choice 1 and 2 are already in degrees Celsius. Now using this formula you need to convert Choice 3 and 4 from Kelvin to Celsius. After you have done that you will get that Choice 3 is 0 degrees Celsius and Choice 4 is 25 degrees Celsius. So now you look at all the choices and you will see that Choice 2 which is 37 degrees Celsius has the greatest average kinetic energy.

40. Look at the periodic table. Barium has 2 valence electrons. So to become stable it needs to have a total of 8 valence electrons. So choice 2 (2 chlorine atoms) is the only reasonable answer. Chlorine has 7 valence electrons and Barium has 2 valence electrons. In order to get a stable number of electrons there has to be two chlorine atoms. Barium will share one valence electron with 7 chlorine valence electrons. The other Barium valence electron will be shared with 7 chlorine valence electrons.

41. Look at Table T and you will find that K= (degrees Celsius) C - 273. Choice 1 and 2 are already in degrees Celsius. Now using this formula you need to convert Choice 3 and 4 from Kelvin to Celsius. After you have done that you will get that Choice 3 is 0 degrees Celsius and Choice 4 is 25 degrees Celsius. So now you look at all the choices and you will see that Choice 2 which is 37 degrees Celsius has the greatest average kinetic energy.

42.