In nature, the chlorine atom has two isotopic forms, 35Cl and 37Cl. The masses of each form are 34.96885amu (75.76%) and 36.9659amu (24.24%), respectively. The average mass of a chlorine atom is .

Explanation:

mass avg = ( abundance 1 x mass 1 = abundance  2 x mass 2 )

                = (  75.76% x   34.96885  +  24.24%    x  36.9659)

                = (  0.7576 x34.96885   +   0.2424 x 36.9659  )

                    =  ( 26.49241  +     8.960534  )

                        = 35.45294 amu

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.