Question

$I{n}_{88}R{a}^{226}$ nucleus, there are:

• A. 138 protons and 88 neutrons
• B. 138 neutrons and 88 protons
• C. 226 protons and 88 electrons
• D. 226 neutrons and 138 electrons

Answer 1

Answer: (B)

${}_z{X}^A={}_{88}R{a}^{226}$
Number of protons $Z=88$
Number of neutrons
$=A=Z=226-88=138$