(a)
(i)
Write two properties of gold which make it the most suitable
metal for ornaments.
(ii
Name two metals which are the best conductors of heat.
(iii)
Name two metals which melt when you keep them on yo
palm.
(b)
Explain the formation of ionic compound CaQ with electron
structure. Atomic numbers of calcium and oxygen are 20 ar
respectively.
Answers
Answer:
ᴀ, i. Two properties of gold :
* It is lustrous (having shining appearance).
* It is malleable that helps it to make different shaped ornaments.
ii. Two metals which are good conductor of heat are Aluminium and Copper.
iii. Gallium and Cesium. ( they melt because of having very low melting point of 29. 76°C and 28.90° C respectively.
Explanation:
b. Calcium reacts with oxygen and forms an ionic compound CaO. Calcium of atomic no. 20, by losing 2 electrons forms calcium ion and by Oxygen of atomic no. 8 gains two electrons to form oxygen ion. The Calcium ion has two units of positive charge and oxygen ion has two units of negative charge and they are held by a strong electrostatic force of attraction to form calcium oxide compound. Thus calcium oxide contains ionic bond.
answer
(i) * lt is lustrous (having shining appearance).
*lt is malleable that helps it to make different shaped ornaments.
(ii) Aluminium and copper
(iii)gallium and cesium