Explain how the visual clues mentioned in this chapter are indications of chemical change as defined in chapter 3

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.

Asample of air with a volume of 2.20m3 at a pressure of 105 kpa and a temperature of 30c is cooled to 10c and the pressure is reduced to 75.0 kpa. what is the new volume? 6.9 1.34 2.56 43.0 2.88

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?