Why aren't the atomic masses of most elements whole numbers

Which of the following elements would you expect to have the lowest ionization energy value? fluorine, lithium, neon, nitrogen

The climate of the continental united states is generally 1. tropical 2. temperate 3. arctic 4. highland

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