Answer:
Isotopes of an element have same number of protons but different number of neutrons. Which means isotopes of an element have same atomic number but different mass number.
The chemical property of an element is determined by the number of electrons. And as all the isotopes have same number of electrons, they have same chemical properties.
Thus as isotopes of an element have same atomic number , they have same number of electrons and protons. As they have different mass number, the number of neutrons will be different. Hydrogen has three isotopes , 
, 
and 
. Thus has no neutron.
Answer:
Explanation:
N and P will have similarity
Electronic configuration of N
2,5
1s²2s²p⁵
Electronic configuration of P
1s²2s²2p⁶3s²3p⁵
Electronic configuration bears similarity.
Both have 5 electrons in their outermost orbits . So they exhibit similarity in their properties. Both belong to the same 15 th group of periodic table.
Sr and Rb too bear much similarity . Both are strongly electro-positive metal , difference in their atomic no being only one.
Adaptation actually and also following control measures on how to avoid it from happening
