✔ 最佳答案
Ag2O有冇covalent character of ionic bond? 如果有, y heat佢就可拆佢ge ionic bond?
Ag2O 有 covalent character of ionic bond，不過由 O 的 electronegativity 很高，被 polarize 的程度較低，所以主要還是 ionic bond.
不清楚你所說的 heat 佢就拆 ionic bond 是甚意思。純粹拆 ionic bond 是指 boiling point 高，但 Ag2O 在常壓下加熱，未到熔點已進行 decomposition 變成 Ag 和 O2。
4Ag2O(s) → 4Ag(s) + O2(g)
但若果考慮以上 decomposition，則不能只考慮 Ag2O(s) 的 strength of ionic bonds，要是要把 the strength of ionic bonds in 4 moles of Ag2O 與 the strength of metallic bonds of 4 moles of Ag 和 the strength of O=O double covalent bonds in 1 mol of O2 比較。
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其實係咪1粒cation+1粒anion先有polarization發生? 如果我地就咁heat AgCl係咪拆唔到佢個bond? 因我見到AgCl ge lattice enthalpy比NaCl ge 更加負ge負數。
In polarization, a cation polarizes a anion.
In AgCl crystals, Ag+ ions polarize Cl- ions. However, this does NOT mean that the bonding forces cannot be broken by heating. Actually, the boiling point of AgCl is 1550oC, and all bonding forces between Ag+ and Cl- ions are completely broken.
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另外, 我想問如果個問題係y mp of NaCL > KCl,
我答因Na+ ge ionic radius < K+, charge density of Na+ >K+, then electrostatic attraction between the Na+ and Cl- > K+ and Cl- , 所以mp of NaCL > KCl.
It is not necessary to consider the charge density. The melting point of an ionic compound depends on:
(1) The charge on the anion, and that on the cation: The higher the charge, the stronger the ionic bond is.
(2) The distance between the anion and cation: The shorter distance between the anion and the cation, the stronger the ionic bond is.
Each of Na+ and K+ carries one positive charge, but Na+ is smaller in size than K+. Therefore, the Na+-Cl- interionic distance in NaCl is shorter than the K+-Cl- interionic distance in KCl. This leads to stronger ionic bonds in NaCl.
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2009-01-05 19:50:03 補充：
lattice enthalpy of ionic compounds 最主要受兩個因素影響：
(1) strength of ionic bonds
(2) lattice structure
所以 lattice enthalpy of ionic compouds 只可粗略比較 strength of ionic bonds.
2009-01-05 23:57:24 補充：
Lattice enthalpy is the energy released when the lattice of 1 mole of ionic compound is formed from its gaseous constituent ions.
(-Lattice enthalpy) is the energy released when the lattice of 1 mole of ionic compound is broken to form its gaseous constituent ions.
2009-01-05 23:58:41 補充：
That is:
The magnitude of energy needed to break the lattice of 1 mole of ionic compounds to form its gaseous constituent ions is equal to the magnitude of lattice enthalpy.
