Which of the following groups of elements is arranged in order of increasing electronegativity?

a. Br < Li < C

b. K < Mg < O

c. Na < K < N

d. Mg < Li < C

e. Ca < Cl < C

EN increases to the right in the table and down a column.

The answer is B.

Electronegativity increases as it goes from Left to Right, and as you go up.

Electronegativity is the measure of an atom's ability to attract electrons towards itself in a chemical bond. In general, electronegativity tends to increase as you move towards the right side of the periodic table and decrease as you move down a group.

Let's analyze each option to determine which one is arranged in order of increasing electronegativity:

a. Br < Li < C: In this group, bromine (Br) is more electronegative than lithium (Li), and carbon (C) is more electronegative than both bromine and lithium. Therefore, this option is not arranged in order of increasing electronegativity.

b. K < Mg < O: In this group, potassium (K) is less electronegative than both magnesium (Mg) and oxygen (O). Therefore, this option is not arranged in order of increasing electronegativity.

c. Na < K < N: This group is arranged in order of increasing electronegativity. Sodium (Na) is less electronegative than potassium (K), and potassium is less electronegative than nitrogen (N). Therefore, option c is arranged correctly.

d. Mg < Li < C: In this group, magnesium (Mg) is less electronegative than both lithium (Li) and carbon (C). Therefore, this option is not arranged in order of increasing electronegativity.

e. Ca < Cl < C: In this group, calcium (Ca) is less electronegative than chlorine (Cl), but carbon (C) is more electronegative than both calcium and chlorine. Therefore, this option is not arranged in order of increasing electronegativity.

Therefore, the correct answer is c. Na < K < N, as it is the only option arranged in order of increasing electronegativity.

To determine the order of increasing electronegativity among the given groups of elements, we need to compare the electronegativity values of each element.

Electronegativity is a measure of an atom's ability to attract electrons towards itself in a chemical bond. The higher the electronegativity value, the more strongly an atom attracts electrons.

- Group a: Br (bromine) is in group 17 of the periodic table with an electronegativity value of 2.96. Li (lithium) is in group 1 with an electronegativity value of 0.98. C (carbon) is in group 14 with an electronegativity value of 2.55. The order of increasing electronegativity in this group is Li < C < Br.

- Group b: K (potassium) is in group 1 with an electronegativity value of 0.82. Mg (magnesium) is in group 2 with an electronegativity value of 1.31. O (oxygen) is in group 16 with an electronegativity value of 3.44. The order of increasing electronegativity in this group is K < Mg < O.

- Group c: Na (sodium) is in group 1 with an electronegativity value of 0.93. K (potassium) is in group 1 with an electronegativity value of 0.82. N (nitrogen) is in group 15 with an electronegativity value of 3.04. The order of increasing electronegativity in this group is Na < K < N.

- Group d: Mg (magnesium) is in group 2 with an electronegativity value of 1.31. Li (lithium) is in group 1 with an electronegativity value of 0.98. C (carbon) is in group 14 with an electronegativity value of 2.55. The order of increasing electronegativity in this group is Li < Mg < C.

- Group e: Ca (calcium) is in group 2 with an electronegativity value of 1.00. Cl (chlorine) is in group 17 with an electronegativity value of 3.16. C (carbon) is in group 14 with an electronegativity value of 2.55. The order of increasing electronegativity in this group is Ca < C < Cl.

Comparing the orders from each group, we can see that the correct option is:

c. Na < K < N