Electonegativity help? :)?

Question

Based on its position on the periodic table, I know that Bromine has a higher electronegativity value than Iodine, but why? Thanks for your help!

Answer 1

Iodine has more levels of electrons than bromine. The extra inner levels of electrons act as a shield to lessen the pull of shared electrons by the iodine nucleus.

Answer 2

Think of the valence shell and the relationship of electrons to protons, and take in mind what you know (or should know) about halogens.

What is the relative size of the nucleus of an atom in regards to its atomic number?

Electronegativity is a measure of an atom to attract electrons in the context of a chemical bond. The type of bond formed is largely determined by the difference in electronegativity between the atoms involved. Atoms with similar electronegativities will share an electron with each other and form a covalent bond. However, if the difference is too great, the electron will be completely transferred from the less electronegative atom to the more electronegative atom, forming an ionic bond. Furthermore, in a covalent bond if one atom pulls slightly harder than the other a polar covalent bond will form. Electronegativity trends are seen in the periodic table. Across a period, non-metals tend to gain electrons and metals tend to lose them due to the atom striving to achieve a stable octet. Down a group, the nuclear charge has less effect on the outermost shells. Therefore, the most electronegative atoms can be found in the upper, right hand side of the periodic table, and the least electronegative elements can be found at the bottom left. Consequently, in general, atomic radius decreases across the periodic table, but ionization energy increases.

All this is saying is Bromine's protons have more "attraction" to electrons than Iodine's. Both atoms need one more electron to complete their octet, but Bromine has a slightly larger force due to the proximity of the nucleus to the valence shell.

Hope this helps

Answer 3

Iodine has more filled electron shells between the positively charged nucleus and the valence electrons. the full shells shield the valence electrons from the nucleus. Therefore, the nucleus doesn't pull as hard on any available electrons.