An element with symbol Cl-having mass number 35 and number of neutron and electron 18. calculate atomic number and number of proton.

Explanation

In sacrifical protection, the surface of the metal is coated with a more reactive metal. Being more reactive, it will take part in electro-chemical reaction and will save other metal. In other words, it will sacrifice itself for the sake of metal to be protected.
For example, iron is generally coated with zinc. This process is known as galvanisation. Here, zinc is more reactive than iron. It is aslo clear from the `E^(@)` values given below :

`Zn(s)rarrZn^(2+)(aq)+2e^(-),E^(@)=-0.76V and Fe(s)rarrFe^(2+)(aq)+2e^(-),E^(@)=-0.44V`
Thus, zinc will be corroded instead of iron. This is also shown in the figure.