Need answered asap for test if a chemical change requires energy, which of the following could be the source of the energy? select one: a. settling the mixture for 20 minutes b. adding more substance to the observed material c. measuring mass from a beam balance d. heating with a flame

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.

How have the greenhouse gasses increased from the year 2000 to 2018

When a scientific theory has been tested and proved by the scientific community, it becomes a law