Answer:
Atom 2 and 4
Step-by-step explanation:
The following data were obtained from the question:
Atom > Proton > Neutron > Electron
1 >>>>> 8 >>>>>> 10 >>>>>> 8
2 >>>> 10 >>>>>> 9 >>>>>> 10
3 >>>>> 9 >>>>>> 9 >>>>>> 9
4 >>>>> 8 >>>>>> 11 >>>>>> 8
Next, we shall determine the mass number of each atom. This can be obtained as illustrated below:
Atom 1:
Proton = 8
Neutron = 10
Mass number =?
Mass number = Proton + Neutron
Mass number = 8 + 10
Mass number = 18
Atom 2:
Proton = 10
Neutron = 9
Mass number =?
Mass number = Proton + Neutron
Mass number = 10 + 9
Mass number = 19
Atom 3:
Proton = 9
Neutron = 9
Mass number =?
Mass number = Proton + Neutron
Mass number = 9 + 9
Mass number = 18
Atom 4:
Proton = 8
Neutron = 11
Mass number =?
Mass number = Proton + Neutron
Mass number = 8 + 11
Mass number = 19
Summary:
Atom >>>> Mass number
1 >>>>>>>> 18
2 >>>>>>>> 19
3 >>>>>>>> 18
4 >>>>>>>> 19
From the above illustration,
Atom 1 and 3 have the same mass number
Atom 2 and 4 also have the same mass number