Question

question 1. use the information provided to complete the table below.
notation atomic number mass number number of protons number of electrons number of neutrons
helium - 4
$^{16}_{8}o$
iodine - 128
$^{40}_{18}ar$

Explanation:

Step1: Recall atomic number rules

The atomic number is equal to the number of protons and for a neutral atom, the number of electrons. It is unique for each element. The mass - number is the sum of protons and neutrons.

Step2: Helium - 4

Helium has an atomic number of 2. So, the number of protons is 2, number of electrons (for neutral atom) is 2. Mass number is 4. Number of neutrons = Mass number - Number of protons = 4 - 2=2.

Step3: $\ce{^{16}_{8}O}$

The sub - script 8 is the atomic number. So number of protons = 8, number of electrons = 8. The mass number is 16. Number of neutrons = 16 - 8 = 8.

Step4: Iodine - 128

Iodine has an atomic number of 53. So number of protons = 53, number of electrons = 53. Mass number is 128. Number of neutrons = 128 - 53 = 75.

Step5: $\ce{^{40}_{18}Ar}$

The sub - script 18 is the atomic number. So number of protons = 18, number of electrons = 18. The mass number is 40. Number of neutrons = 40 - 18 = 22.

Answer:

Notation	Atomic Number	Mass Number	Number of Protons	Number of Electrons	Number of Neutrons
$\ce{^{16}_{8}O}$	8	16	8	8	8
Iodine - 128	53	128	53	53	75
$\ce{^{40}_{18}Ar}$	18	40	18	18	22