How can you determine the number of valence electrons in an atom?

In which situation can a mixture always be called a solution

Will mark brainliest how many electrons can be held in the energy level n = 4?

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.