Ionic bondingIB MYP Sciences: Mind map

Exam questions on Ionic bonding

1. Salt is harvested from shallow seawater pans in Sri Lanka. The salt is sodium chloride, an ionic compound formed when sodium reacts with chlorine. A sodium atom has the electron arrangement 2,8,1 and a chlorine atom has the electron arrangement 2,8,7.
   Describe, in terms of electrons, how sodium atoms and chlorine atoms form the ions in sodium chloride.2 marks
2. A steelworks in Brazil lines its furnaces with magnesium oxide bricks, because magnesium oxide, MgO, can withstand very high temperatures. Magnesium oxide is an ionic compound formed from magnesium, in Group 2, and oxygen, in Group 6.
   Describe what a dot-and-cross diagram of magnesium oxide shows about the electrons.2 marks
3. A student in Dubai is given two white solids, X and Y. One is an ionic compound and the other is a simple molecular substance. Solid X only melts at a very high temperature in a hot flame. It does not conduct electricity as a solid but it does conduct when dissolved in water. Solid Y melts below 100 °C in a warm water bath, does not dissolve in water and does not conduct electricity in any state.
   Explain which solid is the ionic compound.3 marks