Group Trends
Like other groups, the candidates of this family show patterns in its electron configuration, especially the outermost shells resulting in trends in chemical behavior:
| Z | Element | No. of electrons/shell |
|---|---|---|
| 9 | fluorine | 2, 7 |
| 17 | chlorine | 2, 8, 7 |
| 35 | bromine | 2, 8, 18, 7 |
| 53 | iodine | 2, 8, 18, 18, 7 |
| 85 | astatine | 2, 8, 18, 32, 18, 7 |
The halogens show a series of trends when moving down the group—for instance, decreasing electronegativity and reactivity, and increasing melting and boiling point.
| Halogen | Standard Atomic Weight (u) | Melting Point (K) | Boiling Point (K) | Electronegativity (Pauling) |
| Fluorine | 18.998 | 53.53 | 85.03 | 3.98 |
| Chlorine | 35.453 | 171.60 | 239.11 | 3.16 |
| Bromine | 79.904 | 265.80 | 332.00 | 2.96 |
| Iodine | 126.904 | 386.85 | 457.40 | 2.66 |
| Astatine | (210) | 575.00 | 610 (?) | 2.20 |
Read more about this topic: Halogen
Famous quotes containing the words group and/or trends:
“[The Republicans] offer ... a detailed agenda for national renewal.... [On] reducing illegitimacy ... the state will use ... funds for programs to reduce out-of-wedlock pregnancies, to promote adoption, to establish and operate children’s group homes, to establish and operate residential group homes for unwed mothers, or for any purpose the state deems appropriate. None of the taxpayer funds may be used for abortion services or abortion counseling.”
—Newt Gingrich (b. 1943)
“A point has been reached where the peoples of the Americas must take cognizance of growing ill-will, of marked trends toward aggression, of increasing armaments, of shortening tempers—a situation which has in it many of the elements that lead to the tragedy of general war.... Peace is threatened by those who seek selfish power.”
—Franklin D. Roosevelt (1882–1945)