Notice that electronegativity falls as you go down the Group. If you choose to follow this link, use the BACK button on your browser to return quickly to this page. Note: You will find electronegativity covered in detail in another part of this site. It is usually measured on the Pauling scale, on which the most electronegative element (fluorine) is given an electronegativity of 4.0. That means that the atoms are bound to get bigger as you go down the Group.Įlectronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Obviously, the more layers of electrons you have, the more space they will take up - electrons repel each other. The only factor which is going to affect the size of the atom is therefore the number of layers of inner electrons which have to be fitted in around the atom. The outer electrons always feel a net pull of 7+ from the centre. This is equally true for all the other atoms in Group 7. The positive charge on the nucleus is cut down by the negativeness of the inner electrons. In each case, the outer electrons feel a net pull of 7+ from the nucleus. The pull the outer electrons feel from the nucleus. The number of layers of electrons around the nucleus You can see that the atomic radius increases as you go down the Group. Note: You will find atomic radius covered in detail in another part of this site.

The same ideas tend to recur throughout the atomic properties, and you may find that earlier explanations help to you understand later ones. H-Cl)Įven if you aren't currently interested in all these things, it would probably pay you to read the whole page. There is also a section on the bond enthalpies (strengths) of halogen-halogen bonds (for example, Cl-Cl) and of hydrogen-halogen bonds (e.g. You will find separate sections below covering the trends in atomic radius, electronegativity, electron affinity, melting and boiling points, and solubility. This page explores the trends in some atomic and physical properties of the Group 7 elements (the halogens) - fluorine, chlorine, bromine and iodine. Atomic and physical properties of Periodic Table Group 7 (the halogens)ĪTOMIC AND PHYSICAL PROPERTIES OF THE GROUP 7 ELEMENTS (THE HALOGENS)

Atomic radius trend