Breaking chemical bonds and forming the same number of stronger ones should be overall exothermic. Forming bonds is always exothermic. Bond enthalpy is the internal energy change when 2 bonded atoms are separated at constant pressure. Breaking chemical bonds and forming fewer bonds of the same strength should be overall exothermic. Breaking bonds is always endothermic.

In an exothermic reaction, the bonds in the product have higher bond energy (stronger bonds) than the reactants. ... Energy is given off as reactants are converted to products. The energy given off is usually in the form of heat (although a few reactions give off energy as light).

Explanation:

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.