The correct answer is true. It was introduced by Svante Arrhenius that activation energy is minimum amount of energy needed to be supplied or released for a chemical reaction to proceed. It is the energy needed to overcome for a reaction to occur.
I think it might be nomads or movers
(Sorry if wrong)
It will be K-potassium because when you go down a group the electronegativty gets bigger while when you go across the period they get smaller because of the valence electrons. Group 8 has the lowest electronegativty because they have a full outer shell. From left to right on the periodic table it decreases but from top to bottom it increases.
Clouds are a source of Infrared Radiation. When cloud coverage increases, the infrared radiation also increases. So the clouds basically act as space heaters. This emits energy towards the ground, which is what makes cloudy nights warmer. While with clear sky’s all the heat from the day just escapes back into the atmosphere so the temperatures will be colder.
Density = mass/volume
density = 81 grams/0.9 cubic centimetersdensity = 90 grams per cubic centimeter
The density of the sample is 90 grams per cubic centimeter.