Question

To what element does polonium-208 (atomic number 84 decay when it emits an alpha particle?

Answer 1

Alpha decay means the element loses at Helium particle. Helium-4 (atomic number 2)

If polonium will lose 2 protons and 2 neutrons, it will become 204 mass, 82 atomic number. which is Lead (Pb).

Answer 2

Answer:
`_(82)^(204)\textrm {Pb}`

Explanation:-

Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle or a helium nucleus.The atomic number gets reduced by 2 units and the mass number is reduced by 4 units.

General representation of an element is given as:
`_Z^A\textrm{X}`

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

The chemical equation for a alpha decay is represented as:

`_Z^A\textrm{X}\rightarrow _(Z-2)^(A-4)+_2^4\alpha`

`_(84)^(208)\textrm{Po}\rightarrow _(84-2)^(208-4)\textrm {Y}+_2^4\textrm{He}`

`_(84)^(208)\textrm{Po}\rightarrow _(82)^(204)\textrm {Pb}+_2^4\textrm{He}`