Mass number and representation of atom

Q.

What is the mass of an electron in $\mathrm{amu}$?

Q.

Name the following:

The smallest particle of an atom

Q.

The weight of a proton is _____ amu.

Q. A certain sample of element Z contains 60% of ${}^{69}Z$ and 40% of ${}^{71}Z$. What is the average atomic mass of element Z in this sample?

1. 69.2
2. 69.8
3. 70
4. 70.2

Q.

Which of the following sub atomic particle do you think will have no electrical charge and mass equal to the mass of hydrogen atom.

1. Electron

2. None of the above

3. Neutron

4. Proton

Q. Question 2
Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?

Q. How many helium gas contains as many atoms as present the carbon atoms in 24 g of ¹²c.