Question

40k40 +0e 19 20 -1?

complete the following equation o nuclear decay by b-emission

Answer 1

`""_19^40 "K" → ""_text(-1)^0"e" + ""_20^40"Ca"`

Explanation:

I think you asking us to complete this equation:

`""_19^40 "K" → ""_text(-1)^0"e" + ?`

It becomes easier to balance the equation if we replace the "?" with an element symbol `""_x^y"Z"`.

Then the equation becomes

`""_19^40 "K" → ""_text(-1)^0"e" + ""_x^y"Z"`

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.

Sum of superscripts: `40 = 0 + y`, so `y = 40`.

Sum of subscripts: `color(white)(ml)19 = "-1" + x`, so `x = 20`.

We get

`""_19^40 "K" → ""_text(-1)^0"e" + ""_20^40"Z"`

The atomic number of the element is 20, calcium.

∴ The nuclear equation is

`""_19^40 "K" → ""_text(-1)^0"e" + ""_20^40"Ca"`