In: Biology
Ans. Atomic number = Number of protons
Atomic mass = Number of protons + Number of neutrons
Number of electrons = Number of protons
In an atom, the number of electrons (negatively charged) is equal to the number of protons (positively charged) for the overall electrical neutrality of atom.
#1. Number of neutron = Atomic mass – Number of protons
= 300 – 156
= 144
Number of electrons = Number of protons = 156
#2. No.
The atomic number i.e. number of proton is the unique identity of each element. No two different elements can have the same number of proton or same atomic number.
Removal of 1 proton from Ec lowers the atomic number to 155. The resultant nucleus would represent a new element different from Ec.
#3. Yes
Gain of electrons (or removal of electrons) does not affect the number of protons i.e. atomic number of the element. Since the atomic number remains unaffected, the element retains its identity as Ec.
After gaining an electron, the atom gets an additional (-ve) charge on it. It becomes an anion.
For example, chlorine atom (17 protons, 17 electrons) gains an electron to become chloride ion (17 protons, 18 electrons). The atomic number remains unaffected.