Electronegativity is an important idea to know when we talk about how atoms stick together, called chemical bonding.

It tells us how well an atom can attract or grab onto electrons when they are forming a bond. The difference in electronegativity between two atoms is what helps us figure out if they will form ionic bonds or covalent bonds.

1. Ionic Bonds:
   When the electronegativity difference is large (usually greater than 1.7), one atom takes the electrons from the other atom. This creates charged particles known as ions.

You can think of ions as tiny magnets:

• Positively charged ions are called cations.
• Negatively charged ions are called anions.

For example, in table salt, or sodium chloride (NaCl), sodium has an electronegativity of 0.93, and chlorine has an electronegativity of 3.16. The big difference makes them form an ionic bond.

2. Covalent Bonds:
   When the electronegativity difference is small (usually less than 1.7), the atoms will share electrons more equally. This is called a covalent bond.

A good example is water (H₂O). In water, hydrogen has an electronegativity of 2.20, and oxygen has an electronegativity of 3.44. The difference here is about 1.24, which leads to polar covalent bonds. This means the electrons are not shared equally between the atoms.

Knowing about electronegativity helps us predict what type of bonds will form between atoms. This, in turn, affects how substances behave and how reactive they are.