Question

given the table representing the subatomic particles in four different atoms:

atom	number of protons	number of neutrons	number of electrons
e	5	7	5
g	6	7	6
j	12	12	12

which atom has a mass of 12 amu?
a
e
g
j

Explanation:

Step1: Recall mass - number formula

The mass number (in amu) of an atom is the sum of the number of protons and neutrons. Mass number \(A = p + n\), where \(p\) is the number of protons and \(n\) is the number of neutrons.

Step2: Calculate mass number for atom A

For atom A, \(p = 4\) and \(n = 4\). So, \(A_A=4 + 4=8\) amu.

Step3: Calculate mass number for atom E

For atom E, \(p = 5\) and \(n = 7\). So, \(A_E=5 + 7 = 12\) amu.

Step4: Calculate mass number for atom G

For atom G, \(p = 6\) and \(n = 7\). So, \(A_G=6+7 = 13\) amu.

Step5: Calculate mass number for atom J

For atom J, \(p = 12\) and \(n = 12\). So, \(A_J=12 + 12=24\) amu.

Answer:

E. Option E