A. Dalton's theory that atoms could not be divided was incorrect
The arrangement of electron pairs around CH4 and NH3, According to the VSEPR model is the same, because in each case there are the same number of electron pairs around the central atom. So the NH3 and CH4 arrangement of electron pairs is the same because in each case there are the same number of electron pairs around the central atom.
Answer:
Group 18th
Explanation:
The group 18th of periodic table which is composed of Noble gases mainly was missing from the Mendeleev's periodic table. The reason for this is that Noble gases are least reactive, therefore, it was difficult to predict such elements which do not react with other elements.
Answer:
carbon, nitrogen,oxygen,flourine
Answer:
the newspaper one is a chemical change because the chemicals in the paper have reacted with something and turned a different color. the wax one is a physical change because it is a change in the phase of matter, which is always a physical change (still the same substance chemically)
