Typical "give reasons" for this chapter
Point 4 of 4 — Lesson 4: Iron Chemical Properties, Reactions and OxidesQuestion bank: 0 questions (0 with pictures)
05 Typical "give reasons" for this chapter
- Chromium and copper have abnormal electronic configurations: a half-filled (3d⁵) or full (3d¹⁰) sublevel makes the atom more stable.
- Chromium is active but resists atmospheric attack: a non-porous oxide layer of larger volume than the metal forms on its surface.
- Cu, Ag and Au are transition elements: their ions (Cu²⁺, Au³⁺) have incomplete d sublevels.
- The decrease in atomic radius across the first series is small: increasing nuclear attraction is opposed by increasing repulsion between 3d electrons.
- Transition elements have high melting and boiling points: strong metallic bonds involving both 4s and 3d electrons.
- Most transition-element compounds are attracted by a magnet: they contain unpaired d electrons.
- Iron reacts with dilute acids to give iron(II) not iron(III) salts: the liberated hydrogen reduces Fe³⁺ to Fe²⁺.
- Scandium does not form Sc²⁺: it loses all three outer electrons to reach the stable argon structure.
- Iron(III) chloride is paramagnetic: Fe³⁺ is 3d⁵ with five unpaired electrons.
- Concentrated nitric acid makes iron passive: a thin protective oxide layer forms on the surface.
- Most transition elements are catalysts: their 4s and 3d electrons form temporary bonds with reactants, lowering the activation energy.
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