Question

${}_1^2\text{H}$ + ${}_4^9\text{Be}$ $\to$ $X$ + ${}_2^4\text{He}$ identify $X$

• A. ${}_3^7\text{Li}$
• B. ${}_3^6\text{Li}$
• C. ${}_4^7\text{Be}$
• D. $2$ ${}_2^3\text{He}$

Answer 1

The correct option is A ${}_3^7\text{Li}$

The given eq. is:

${}_1^{2}H{+}_4^{9}Be⟶X{+}_2^{4}He$

Let X is an atom with atomic no. x and atomic weight y i.e. ${}_x^{y}X$

For a balanced equation:

$1+4=x+2$

or $x=3$

and $2+9=y+4$

or $y=7$

which is best suited to ${}_3^{7}Li$ out of the given options .