Assertion : After emission of one `alpha`-particle and two `beta`-particles, atomic number remains unchanged.
Reason : Mass number changes by four.

Successive emission of an alpha -particle and two beta -particles by an atom of an element result in the formation of its

With the emission of beta -particle from an atom of an element, its atomic number

(A) The position of an element in periodic table after emission of one alpha and two beta -partilce remians unchanged. (R ) Emission of one alpha and two beta particles gives isotope of the parent element which acquires same position in the periodic table.

(A) The position of an element an element in periodic in table after emission of one alpha and two beta -partilce remians unchanged. (R ) Emission of one alpha and two beta particles gives isotope of the parent element which acquires same position in the periodic table.