Question

1. Name the three sub-atomic
particles of an atom.
2. Helium atom has an atomic mass
of 4 u and two protons in its
nucleus. How many neutrons
does it have?
please friends answer in brief ​

Answer 1

Explanation:

three sub atomic particles of an atom is

1.proton

2.neutron

3.electron

Answer 2

Answer:

• Atoms are composed mainly of protons, neutrons, and electrons.
• No. of Protons + No. of Neutrons = (No. of electrons) = Mass number.
• The mass number of He = 4
• No.of Protons in He = 2
• Using the formula,
• No. of Protons + No. of Neutrons = Mass number.
• No. of Neutrons = Mass number - No.of Protons
• No. of Neutrons = 4-2 = 2
• Therefore, No.of Neutrons in Helium atom = 2
• The mass of an atom is given by the sum of the masses of protons and neutrons present in the nucleus. Since helium atom has a atomic mass of 4 u and it has two protons. Two protons contribute 2 u to atomic mass. Hence, it must contain 2 neutrons

Explanation:

hope you appreciate this ans