electronegativity trends

[Shreya Tamatam 3B]

Can anyone please explain why electronegativity decreases down a group and increases as you move across a period? Thank you!

[Yousif Jafar 1G]

Electronegativity is the tendency to attract an electron. So, as you move across a period there are more protons, so the electronegativity increases. The electronegativity decreases as you move down because of the increased distance between the electron and the nucleus and more electrons are shielding its charge so it is less electronegative.

[Sean_Rodriguez_1J]

As you go down a group, more sub shells are added that are farther and farther away from the nucleus, making the atoms less likely to attract electrons. As you move across a period, the amount of protons in the nuclei of the atoms increase, increasing the nuclear charge and the ability of the atom to pull electrons towards it.

[Summer de Vera 2C]

So do electronegativity trends essentially rely on electron shielding ? As do the other periodic table trends ?

[John Kim Lec3Dis3L]

I think it's not so much that there is a causal relationship between electronegativity and electron shielding as a correlative relationship for these periodic trends.

[Julia Jones 1G]

across the period, the nuclear charge and ability of the atom to pull electrons increases. As you go down, the atoms attract electrons less.

[LedaKnowles2E]

Electronegativity is calculated using electron affinity and ionization energy; high electron affinity and ionization energy mean high electronegativity. Electron affinity and ionization energy decrease down a group because as you go down a group, the atoms get larger, and so the electrons are farther from the nucleus and are therefore less attracted to the nucleus and easier to remove. Ionization energy and electron affinity increase across a period because the electrons are pulled closer to the nucleus, making them harder to remove, and also as the electron shells fill and get closer to octet, they want more electrons to fill it completely.
Electronegativity follows the same trends.