Are elements considered to be substances? a No, because they are generally unreactive

b Yes, because they can be either homogeneous or heterogeneous

c Yes, because they have a definite composition

d No, because they have a variable composition

Asample of neon occupies a volume of 375 ml at stp. what will be the volume of neon if the pressure is reduced to 90.0 kpa? a. 422 ml b. 422 l c. 333 ml d. 333 l

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.

In which environment would primary succession occur? a forest with a few remaining trees after a recent wildfire an area of exposed rock after a glacier melts away beach that is exposed to the air at low tide an abandoned baseball field in a small town