Electronegativity (EN) is a property that describes an atom\u2019s attraction for electrons in a bond. This property determines the type of bond which forms between two atoms. An atom with a higher electronegativity means it has more attraction for electrons in a bond. Flourine has the highest electronegativity and is assigned a value of around 4. The periodic trend for electronegativity is that it increases as you go up and to the right of the periodic table.<\/p>\n
The difference in electronegativity between the two bonding atoms is calculated to determine the bond type. There is a general scale used to determine the bond types. If the difference in electronegativity is between 3.3 – 1.7, the bond is ionic. If the difference is from 0 – 1.7, the bond is covalent. More specifically, if it is between 0 – 0.5, the bond is non-polar covalent. A polar covalent bond is formed between 0.5 – 1.7.<\/p>\n
Molecular Range: 0 – 1.7<\/p>\n
– Non-polar covalent: 0 – 0.5<\/p>\n
– Polar covalent: 0.5 – 1.7<\/p>\n
Ionic Range: 1.7 – 3.3<\/p>\n
<\/p>\n
Examples:<\/p>\n
1) Na and Cl<\/p>\n
Electronegativity of Na = 0.93<\/p>\n
EN of Cl = 3.16<\/p>\n
Difference in EN = 3.16 – 0.93 = 2.23<\/p>\n
Therefore, the bond is ionic.<\/p>\n
2) H and O<\/p>\n
EN of H = 2.2<\/p>\n
EN of O = 3.44<\/p>\n
Difference in EN = 3.44 \u2013 2.2 = 1.24<\/p>\n
Therefore, the bond is polar covalent.<\/p>\n
3) N and O<\/p>\n
EN of N = 3.04<\/p>\n
EN of O = 3.44<\/p>\n
Difference in EN = 3.44 \u2013 3.04 = 0.4<\/p>\n
Therefore, the bond is non-polar covalent.<\/p>\n