Question

1d. complete the table below. (2 points)
element name mass number protons neutrons electrons (neutral atom)
barium 138

16 34

Explanation:

Step1: Recall atomic number of barium

The atomic number of barium (Ba) is 56. In a neutral atom, the number of protons is equal to the atomic number. So for barium, the number of protons is 56.

Step2: Calculate neutrons for barium

The mass - number formula is $Mass\ number=Protons + Neutrons$. Given the mass number of barium is 138 and protons is 56. Then $Neutrons=Mass\ number - Protons=138 - 56 = 82$. In a neutral atom, the number of electrons is equal to the number of protons, so electrons for barium is 56.

Step3: Identify element with 16 protons

The element with 16 protons is sulfur (S).

Step4: Calculate mass number for sulfur

Using the mass - number formula $Mass\ number=Protons + Neutrons$. Given protons = 16 and neutrons = 34, then $Mass\ number=16 + 34=50$. In a neutral atom, the number of electrons is equal to the number of protons, so electrons for sulfur is 16.

Answer:

Element Name	Mass Number	Protons	Neutrons	Electrons (neutral atom)
Sulfur	50	16	34	16