Answer:
In Haloarenes the C atom to which the X group is attached is SP2 hybridized thus it is become difficult to replace it by the Nucleophile. Since arenes and Vinyl halides are electron rich molecules due to presenceof n bonds, they repel Nucleophile attacking them.
What your question for number 3
Answer:
A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons. An element is a substance that is made entirely from one type of atom
Explanation:
so In simple terms an atom contains Protons and Electrons and can be found in an Element, but an element comprises of atoms which come together to form up that particular Element
Answer:
16,,24Mg 17,,a24.1 18a mass number of the most abundant isotope
Explanation:
atomic number of Mg is 12 ,therefore its mass number should be the value that is very close to 24.
24.1 is the value of thee most abundant isotope.