How many neutrons does element x have if it’s atomic number is 35 it’s mass number is 91

The mass number is the total accumulative mass of neutrons and protons and the atomic number is synonymous with the number of protons. Therefore to find the number of neutrons in a given element, just subtract the mass number with the atomic number

In your example, it would be 91-35

This is what i found on google “according to the collision theory, the following criteria must be met in order for a chemical reaction to occur: molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. molecules must collide with the proper orientation.” i hope this information you.

Alkaline earth metals are found in group 2 of the periodic table.