Answer: <u>Four</u>Explanation: Calcium Sulfide is an ionic compound made up of Ca²⁺ and S²⁻.
Ca²⁺ is formed as,
Ca → Ca²⁺ + 2 e⁻
These two electrons are accepte by Sulfur as,
S + 2 e⁻ → S²⁻
So, before accepting 2 electrons S was having six valence electrons, after accepting two electrons from Ca it has 8 electrons which are present in four pairs as shown below,
Carbon:
1s is filled. 2s is filled. 2p is shown to contain two electrons in one orbital and no electrons in the other two orbitals.
The water molecules received enough energy through the heat for them to change to a liquid state by unfixing themselves from their fixed positions.
When the block of iron is placed in water the volume of water that is displaced is 27.0 cm³
<u><em> calculation</em></u>
The volume water that is displaced is equal to volume of block of the iron
volume of block of iron = length x width x height
length= 3 cm
width = 3 cm
height = 3 cm
volume is therefore = 3 cm x 3 cm x 3 cm = 27 cm³ therefore the volume displaced = 27 cm³ since the volume of water displaced is equal to volume of block.