State the appearance of the halogens at r.t.p. as: (a) chlorine, a pale yellow-green gas (b) bromine, a red-brown liquid (c) iodine, a grey-black solid

The Periodic Table – Group VII (Halogens)

Objective

State the appearance of the halogens at room temperature:

(a) Chlorine – pale yellow‑green gas

(b) Bromine – red‑brown liquid

(c) Iodine – grey‑black solid

Quick Reference Table

ElementSymbolAppearanceState at RTCommon Example
ChlorineClPale yellow‑green gasGasBleach (NaClO)
BromineBrRed‑brown liquidLiquidBromine lamps (red light)
IodineIGrey‑black solidSolidIodised salt (NaI)

Analogies & Everyday Examples

  • 🔬 Chlorine feels like a greenish spark in the air – think of the bright green glow of a firefly, but in gas form.

  • 🟥 Bromine is the liquid that looks like a deep red‑brown puddle, similar to the colour of a ripe beetroot juice.

  • ⚫ Iodine is the solid that looks like a dark charcoal block, like the black part of a charcoal stick.

Exam Tips

Tip 1: Remember the order of states – gas, liquid, solid – and match them with the colour cues: green (gas), red (liquid), black (solid).

Tip 2: Use the mnemonic “Green Gas, Red Liquid, Black Solid” to recall the sequence.

Tip 3: When answering, write the chemical symbol with the correct state: e.g., \$\ce{Cl2(g)}\$, \$\ce{Br2(l)}\$, \$\ce{I2(s)}\$.

Tip 4: Practice drawing the halogens in a small table; this visual aid helps you remember both appearance and state quickly.