Answer
(a)
X = $^0_{-1}\beta$
(b)
X = $^{40}_{18}Ar$
(c)
$^{4}_2He$ or $^4_2\alpha$
(d)
X = $_0^1n$
Work Step by Step
1. Find the atomic number of X:
(a) 53 = 54 + x
x = -1
X = $^0_{-1}\beta$
(b) 19 + (-1) = x
x = 18
X = Ar
(c) 27 + 0 = 25 + x
x = 2
X = $He$ or $\alpha$
(d) 92 + 0 = 40 + 52 + 2x
x = 0
X = $_0^1n$
2. Find the atomic mass of X:
(b) 40 = 0 + x
x = 40
(c) 59 + 1 = 56 + x
x = 4
