group 7 - the halogens Flashcards
What does it mean that halogens are diatomic?
They exist as molecules of 2 atoms, written as X2 in elemental form.
What is the meaning of the term ‘halogen’?
It means ‘salt former’, as they react readily with metals to form salts.
What type of molecules are halogens?
They are simple covalent molecules.
What is the reactivity of halogens?
They are highly reactive.
What type of elements are halogens?
They are non-metals.
What type of ions do halogens form?
They form 1- ions.
How does the density and color of halogens change down the group?
They become denser and darker down the group.
What is the physical state and color of fluorine (F2)?
Pale yellow, highly corrosive gas.
What happens when chlorine (Cl2) is dissolved in water?
It dissolves slightly to form a pale green solution.
What is the physical state and color of bromine (Br2)?
Red-brown liquid.
What color solution does bromine form when dissolved in water?
Orange solution.
What is the physical state and color of iodine (I2)?
Grey solid.
What color solution does iodine form when dissolved in water?
Pale brown solution.
What trend in atomic radius is observed down the group of halogens?
Atomic radius increases down the group.
What trend in boiling point is observed down the group of halogens?
Boiling point increases down the group.
What holds simple covalent molecules together?
Van der Waals forces.
What trend in electronegativity is observed down the group of halogens?
Electronegativity decreases down the group.
What is the trend in reactivity of halogens down the group?
Reactivity decreases down the group.
What happens to the first ionization energy of halogens down the group?
It decreases down the group.
What is the trend in oxidizing ability of halogens down the group?
Oxidizing ability decreases down the group.
What is a displacement reaction in the context of halogens?
A smaller halogen displaces a larger halide from its compound.
What is the result of adding silver nitrate to a halide solution?
It forms a precipitate with the halide.
What color precipitate does silver chloride (AgCl) form?
White precipitate.
What color precipitate does silver bromide (AgBr) form?
Cream precipitate.
What color precipitate does silver iodide (AgI) form?
Yellow precipitate.
What trend is observed in the solubility of silver halide precipitates down the group?
Solubility decreases down the group.
What is the trend in reducing power of halides down the group?
Reducing power increases down the group.
What is the reaction of sodium chloride with sulfuric acid?
It is an acid-base reaction producing HCl gas.
What is the observation when sodium bromide reacts with sulfuric acid?
Steamy fumes of HBr and brown fumes from Br2.
What is the observation when sodium iodide reacts with sulfuric acid?
Steamy fumes of HI and solid black iodine.
What is the disproportionation reaction of chlorine with cold water?
Cl2 + H2O ⇌ HClO + HCl.
What is produced when chlorine reacts with cold dilute sodium hydroxide?
Sodium chlorate (NaClO), sodium chloride (NaCl), and water.
What is the main use of chlorine in water treatment?
To kill bacteria.
What is the effect of sunlight on chlorine reacting with water?
It produces hydrochloric acid and oxygen.
