The following statements which are correct :
(1) Magnesium chloride and Magnesium Sulfate are Ionic compounds.
(4)Ionic compounds have higher melting and boiling points than covalent compounds
Explanation for each point :
(1) MgCl and MgSO4 are iconic compounds because they exist as solids due to strong electrostatic forces of attraction and are soluble in polar solvents.
The bond formed here is electrovalent(or ionic bond).
(2) Methane and Carbon dioxide are NOT ionic compounds .
•They are Covalent compounds
•In methane , CH4 , carbon is attached to four hydrogen atoms as Central atom C has 8 valence electrons.
•In carbon dioxide , CO2 it is a polar covalent bond and central atom C gas 8 valence electrons.
(3)An ion that gains an electron has a NEGATIVE charge not positive charge.
When an electron loses an electron it will have a positive charge , this process is known as Ionization.
(4) Ionic compounds have higher melting and boiling points than covalent compounds because the bonds in ionic compounds have high forces of electrostatic and hence also requires high energy to break .
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What are Ionic Compounds(Ionic bond)?
•If the two oppositely charged ions have strong electrostatic forces of attraction then a Ionic bond is formed.
•This formation is a redox process.
•These are good electrical conductors in molten state.
What are Covalent bonds/compounds?
•If the bond is formed between two atoms by mutual sharing of the outer most electrons then it’s known as covalent bond.
•Polar covalent bond are formed when two dissimilar electro negative atoms have mutual sharing of electron pairs.
•These have low melting and low boiling points
•These are not electrical conductors as they don’t have free electrons in them.