(a) What is the trend in electronegativity going from left to right in a row of the periodic table? (b) How do electronegativity values generally vary going down a column in the periodic table? (c) How do periodic trends in electronegativity relate to those for ionization energy and electron affinity?

Going from left to right in a row of the periodic table, electronegativity generally increases. This is because, in the same period, the number of protons in the nucleus increases while the electrons are added to the same energy level. As a result, there is a more substantial pull on the electrons towards the nucleus, leading to a higher electronegativity value.

Going down a column in the periodic table, electronegativity values tend to decrease. This is because, as we move down a group, the number of electron shells increases. This causes the outer electrons to be less attracted to the nucleus due to shielding effect, resulting in a reduced electronegativity value.

Electronegativity, ionization energy, and electron affinity are closely related properties. Electronegativity is the ability of an atom to attract a bonding pair of electrons, ionization energy is the energy required to remove an electron from an atom, and electron affinity is the energy change when an electron is added to an atom. As we move from left to right in a row of the periodic table, electronegativity values and ionization energy increase, as does electron affinity (except for noble gases, which have very low electron affinity). This is because the effective nuclear charge increases across a period, which results in stronger electrostatic attraction between electrons and the nucleus. As we move down a column in the periodic table, electronegativity values and ionization energy decrease, and electron affinity also generally decreases. This is due to the increased shielding effect due to additional electron shells, which reduces the effective nuclear charge experienced by the outermost electrons. In summary, periodic trends in electronegativity are related to trends in ionization energy and electron affinity because they are all influenced by atomic size, effective nuclear charge, and shielding effect.