Periodic Trends Electronegativity

Electronegativity  An atoms’ ability to attract electrons in a chemical bond  High EN = attracts e’s well  Low EN = attracts e’s poorly

Electronegativity Trends: 1.EN decreases as you move down a group WHY? As you move down a group, the valence energy level gets further from the nucleus making it harder for electrons to be attracted to the nucleus because the nucleus has less control

2.EN increases as you move from left to right in a period WHY? As you move right on a period, the number of protons in the nucleus of the atom increases, meaning electrons are more attracted to the increasing positive charge

Generally Increasing Electronegativity

General Rule:  The larger the size, the smaller its EN  The smaller the size, the larger the EN

Ionization Energy vs Electronegativity  Large atoms – low EN, low IE  Small atoms – high EN, high IE

What has the higher EN?  N or S? NNNN  It is smaller therefore its nucleus has more control over its electrons allowing it to attact an electron more easily.