Why are some isotopes radioactive?

Is anybody know when John Dalton propose his principle of the atomic theory?

The following values are the only allowable energy levels of a hypothetical one-electron atom: E₆ = - 2 x 10⁻¹⁹ J E₅ = - 7 x 10⁻¹⁹ J E₄ = - 11 x 10⁻¹⁹ J E₃ = - 15 x 10⁻¹⁹ J E₂ = - 15 x 10⁻¹⁹ J E₁ = - 15 x 10⁻¹⁹ J (a) If the electron were in the n =

The new substances that result in a chemical reaction are called A. products B. Reactants C. Ending substances D. Final substances

A certain reaction has an activation energy of 51.64 kj/mol. At what temperature Kelvin will the reaction be 5.50 times faster than it did at 343K?

5 examples of a combustion reactions.

How long does it take earth to complete one rotation

What are the relative numbers of h3o + and oh - ions in an acidic and alkaline and a neutral solution?

Chloroform was used as an anesthetic for childbirth and surgery during the nineteenth century. Write the molecular formula of chloroform.

Why are alloys generally used to make everyday objects

What types of matter could be separated by physical methods?