Halogens in Chemistry

Halogen reactivity decreases down the group due to decreasing core charge. As you descend, the outermost electron is further away from the nucleus (and its attraction) and thus easier to remove (less reactive).

Halogens exhibit a change in state from gas (F₂ and Cl₂) to liquid (Br₂) to solid (I₂) as you move down the group. This occurs due to increased intermolecular forces (van der Waals forces) caused by larger electron clouds and greater polarizability.

Halogens exist as diatomic molecules (e.g., Cl₂) through covalent bonding, where two halogen atoms share one pair of electrons to achieve a stable octet.

<p>The reaction produces bromine and potassium chloride. The balanced chemical equation is: Cl₂(g) + 2KBr(aq) → 2KCl(aq) + Br₂(l). This is a single displacement/redox reaction, where chlorine is a stronger oxidizing agent than bromine and therefore displaces it from the bromide ion.</p> Signup and view all the answers

<p>The precipitate formed is silver iodide (AgI). This reaction is used to distinguish between halide ions because the color of the precipitate is unique for each halide (AgCl-white, AgBr-cream, AgI-yellow).</p> Signup and view all the answers

<p>The oxidizing strength of halogens decreases as you go down the group. This is because the attraction between the nucleus and the incoming electron decreases with increasing atomic size (due to the increasing distance between the nucleus and the outer electrons).</p> Signup and view all the answers

<p>Melting and boiling points of halogens increase as you descend the group. This is attributed to the increase in van der Waals forces of attraction between the molecules. Larger molecules have stronger van der Waals forces, requiring more energy to overcome them, leading to higher melting/boiling points.</p> Signup and view all the answers

<p>The Dead Sea has a very high salinity, significantly higher than the ocean. This high salt concentration is largely responsible for the buoyancy experienced by people in the Dead Sea. The high density of the saline water causes objects, including people, to float more easily.</p> Signup and view all the answers

<p>Halogens, with seven outer electrons, achieve stability by gaining one electron to complete their octet configuration. They can accomplish this through either ionic bonding with metals or covalent bonding with nonmetals. In ionic bonding, they gain an electron from a metal atom, forming a halide ion. In covalent bonding, they share an electron with another nonmetal atom.</p> Signup and view all the answers

<p>The reaction is: Cl₂(g) + 2NaOH(aq) → NaCl(aq) + NaClO(aq) + H₂O(l).</p> Signup and view all the answers

Group 7 elements on the periodic table, highly reactive non-metals.

Reactivity decreases down the group from fluorine to astatine.

Halogens exist as diatomic molecules (e.g., F₂, Cl₂).

Formed when halogens gain electrons from metals, becoming negatively charged.

Halogens share electrons with non-metals to achieve stability.

Halogen color becomes darker from top to bottom of the group.

Increase as you move down the group of halogens.

Reactions where a halogen displaces another from a compound.

Forms precipitates when silver ions react with halide ions.

Highest salt concentration, making it the lowest point on Earth.