Question

What happens when two atoms form a bond ?

Answer 1

Hint: To reach a maximum outer energy level, which is the most stable arrangement of electrons. Atoms form chemical bonds to make their outer electron shells more stable. The type of chemical bond maximizes the stability of the atoms that form To render their outer electron shells more stable atoms form chemical bonds. The chemical bond type maximises the stability of the atoms forming it.

Complete answer:
You can use the periodic table to make several predictions about whether atoms will form bonds and what type of bonds they might form with each other. On the far right-hand side of the periodic table is the group of elements called the noble gases. Atoms of these elements (e.g., helium, krypton, neon) have full outer electron shells. These atoms are stable and very rarely form bonds with other atoms.
One of the best ways to predict whether atoms will bond with each other and what type of bonds they will form is to compare the electronegativity values of the atoms. Electronegativity is a measure of the attraction an atom has to electrons in a chemical bond.
A large difference between electronegativity values between atoms indicates one atom is attracted to electrons, while the other can accept electrons. These atoms usually form ionic bonds with each other. This type of bond forms between a metal atom and a nonmetal atom.
If the electronegativity values between two atoms are comparable, they may still form chemical bonds to increase the stability of their valence electron shell. These atoms usually form covalent bonds.
You can look up electronegativity values for each atom to compare them and decide whether an atom will form a bond or not. Electronegativity is a periodic table trend, so you can make general predictions without looking up specific values. Electronegativity increases as you move from left to right across the periodic table (except for the noble gases). It decreases as you move down a column or group of the table. Atoms on the left-hand side of the table readily form ionic bonds with atoms on the right side (again, except the noble gases). Atoms in the middle of the table often form metallic or covalent bonds with each other.

Note:
You may be confused about whether the stability of an atom is related to its electrical charge. An atom that gains or loses an electron to form an ion is more stable than a neutral atom if the ion gets a full electron shell by forming the ion. Because oppositely charged ions attract each other, these atoms will readily form chemical bonds with each other.