Examples of chemical changes in digestion ,1.Stomach acids breaking down food 2.Tongue rolling food into bolus
3. Saliva breaking down sugar in foods
4.Stomach juices dissolving fats
5.Tongue pushing food down esophagus.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

c. 75.7

i think that is the right

increased stability in the completion of fluorine's outer shell.