Question

Which of the following are $\alpha$-emitters?

• A. ${}^{212}Po$
• B. ${}^{226}Ra$
• C. ${}^{5}He$
• D. ${}^{3}H$

Answer 1

The correct option is B ${}^{226}Ra$

${}^{226}Ra$ are the $\alpha$ emiters.
When ${}^{226}Ra$ decays by alpha emission it emits a helium nucleus (alpha particle) which reduces its mass number by 4 and its atomic number by 2. So, the resulting nucleus is ${}^{222}Rn$.