Question

Answer these questions based on 234.04360 as the atomic mass of thorium-234. The masses for the subatomic particles are given. Round the mass defect to the 5th decimal place. mass of a proton: 1.00728 amu mass of a neutron: 1.00866 amu How many protons does Thorium have? How many neutrons does Thorium-234 have? Calculate the mass defect for the isotope thorium-234 = amu

Answer 1

How many protons does Thorium have? 90

How many neutrons does Thorium-234 have? 144

Calculate the mass defect for the isotope thorium-234 1.85864 amu

Answer 2

The number of protons in Thorium, 90

The number of neutrons in Thorium, 144

The mass defect for the isotope thorium-234 = 1.85864 amu

Solution : Given,

Atomic mass of Thorium-234 = 234.04360 amu

Mass of a proton = 1.00728 amu

Mass of a neutron = 1.00866 amu

First we have to determine the number of protons present in Thorium.

The atomic number of Thorium = 90

As the number of proton is equal to the atomic number. So, the number of proton is, 90

Now we have to determine the number of neutrons in Thorium.

Number of neutrons = Atomic mass - Atomic number

Number of neutrons = 234 - 90 = 144

Now we have to calculate the mass defect for the isotope Thorium-234.

Formula used :

`\Delta m=(n* m_P)+(x* m_N)-M`

where,

m = mass defect

n = number of protons

x = number of neutrons

`m_P` = mass of proton

`m_N` = mass of neutron

Now put all the given values in the above formula, we get the mass defect.

`\Delta m=(90* 1.00728)+(144* 1.00866)-234.04360`

`\Delta m=1.85864amu`

Therefore, the mass defect for the isotope thorium-234 is, 1.85864 amu