Arrange the elements C, O, and H in order of increasing electronegativity
a) C < O < H
b) H < C < O
c) C < H < O
d) O < C < H
The Correct Answer and Explanation is :
The correct answer is b) H < C < O.
Explanation:
Electronegativity refers to the ability of an atom in a molecule to attract shared electrons in a covalent bond. The electronegativity values of the elements carbon (C), oxygen (O), and hydrogen (H) are critical for understanding how these atoms interact in chemical bonds.
- Hydrogen (H) has the lowest electronegativity among the three. Its electronegativity is approximately 2.20 on the Pauling scale. Hydrogen is a nonmetal but has only one electron in its valence shell, which limits its ability to attract electrons strongly in a bond.
- Carbon (C) comes next with a higher electronegativity value of about 2.55 on the Pauling scale. Carbon is a nonmetal with four valence electrons, and it can form four covalent bonds to complete its octet. Although it is more electronegative than hydrogen, it still does not pull electrons as strongly as oxygen.
- Oxygen (O) has the highest electronegativity of the three, with a value of about 3.44. Oxygen is highly electronegative due to its smaller atomic radius and high effective nuclear charge, which allows it to attract electrons more strongly than both hydrogen and carbon.
Electronegativity Trends:
- Electronegativity generally increases as you move from left to right across a period in the periodic table.
- It decreases as you move down a group. Oxygen, being in Group 16 and Period 2, has the highest electronegativity, while hydrogen and carbon are in Group 1 and Group 14, respectively, with hydrogen being the least electronegative.
Thus, the correct order from least to most electronegative is: H < C < O.