MgO melts at a temperature more than 1500 °C higher than that of NaCl
CHEMISTRY · Single correct · ISC · Chemistry · Chemical Bonding and Molecular Structure · Chemical Bonding and Molecular Structure
Problem
MgO melts at a temperature more than 1500 °C higher than that of NaCl. Which statement best accounts for this difference?
(a) Because the Mg2+ ion is considerably smaller than Na+, the ions in MgO are packed more closely together, giving stronger ionic attractions that require a higher melting temperature.
(b) The Mg2+ and O2− ions in MgO carry twice the charge of the ions in NaCl, producing much stronger Coulombic attractions that require more energy to break.
(c) MgO forms a three-dimensional covalent network, whereas NaCl is held together only by ionic attractions.
(d) Because MgO has a greater molar mass than NaCl, its London dispersion forces are significantly stronger.