Which element exists as single atoms?

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.

If i add water to oil what will happen

A20 liter cylinder of helium at a pressure of 150 atm and a temperature of 27°c is used to fill a balloon at 1.00 atm and 37°c. what is the volume of the balloon? a. 0.14 liters b. 3000 liters c. 2900 liters d. 2400 liters e. 3100 liters