Question

1. the valence electrons in atoms are shielded from the attractive pull of the nucleus by inner shells of electrons. this is called the shielding effect. do you think the reactivity of the halogens relates to the shielding effect? explain your reasoning.

Explanation:

The shielding effect affects the effective nuclear charge experienced by valence - electrons. Halogens need to gain one electron to achieve a stable octet. As we move down the halogen group, the number of electron shells increases, increasing the shielding effect. This reduces the effective nuclear charge on the outermost electrons, making it harder for the nucleus to attract an additional electron. So, reactivity decreases down the group due to the increasing shielding effect.

Answer:

Yes, the reactivity of halogens relates to the shielding effect. As we move down the halogen group, the shielding effect increases, reducing the effective nuclear charge on valence electrons, and decreasing reactivity as it becomes harder to attract an extra electron.