Question

Which element has highest electronegativity?
A. $K$
B. $Ca$
C. $Br$
D. $Kr$
E. $Zn$

Answer 1

Hint: Try to recall that electronegativity is a measure of how strongly atoms attract bonding electrons to themselves. You should know that the more an element is electronegative, the more is its tendency to distort the electron cloud of the other atom.

Complete step by step solution:
We know that electronegativity of an element is defined as the tendency of its atom to attract the shared pair of electrons in a bonded state.
Unlike ionization energy and electron affinity, electronegativity of an element is not a measurable quantity.
A lot of numerical scales such as Pauling scale, Mullikan scale and Alfred- Rochow scale have been developed to measure electronegativity of an element.
It has been seen that on moving from left to right along a period in a periodic table, electronegativity of successive elements tends to increase. This happens because as we move from left to right along a period, nuclear charge increases and it becomes easier to attract the shared electron pair.
Now coming to the question, you can observe that all elements given in options belong to the 3rd period of the periodic table.
So, when we go from left to right along the 3rd period, $Br$ and $Kr$ are present on the rightmost side of the periodic table.
Since, we know that $Kr$ is an unreactive element, so $Br$ will be the most electronegative element.
Hence, we can conclude that option C is the correct option to the given question.

Note: You should remember that electronegativity is a property of bonded atoms.
Also, one should remember that electronegativity changes regularly in a period but there are some exceptions in a group.