Identify each of the following as either a physical change or a chemical change. explain your answers.

a. a piece of wood is sawed in half.
b. milk turns sour.
c. melted butter solidifies in the refrigerator.

A would be Physical

B would be Chemical

and C would be Physical

Explanation:

A would be physical because the wood is physically changing

B would be chemical because it's still milk but it now had clumps called curds and a very sour taste

C would be physical because the melted butter is physically changing from melted butter to solid butter.

Hope this helps.

n has four pairs of electrons in the valence shell, electrons repel one another ,n has 7 protons in its nucleus, and since n has 7 protons, it must fill the second shell, giving it 4 pairs of electrons. the electrons form 3 bonds and 1 lone pair of electrons. each pair of electrons repels the other pairs, so they are equally far apart.

so all of the above

beta decay is the answer