Light is not considered as a matter, why?

How many atoms are there in 5.70 mol of mg

The diagram below shows the movement of particles. what does this piece of evidence best support? the collision theory the maxwell-boltzmann distribution the effect of pressure on reaction rates the effect of temperature on reaction rates

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope