Question

a) State the postulates of Bohr’s atomic model.
b) Define the terms atomic number and atomic mass with one example

Answer 1

Answer:

Explanation:

(a) Postulates of Bohr’s Model of an Atom

In an atom, electrons (negatively charged) revolve around the positively charged nucleus in a definite circular path called orbits or shells.

Each orbit or shell has a fixed energy and these circular orbits are known as orbital shells.

The energy levels are represented by an integer (n=1, 2, 3…) known as the quantum number. This range of quantum number starts from nucleus side with n=1 having the lowest energy level. The orbits n=1, 2, 3, 4… are assigned as K, L, M, N…. shells and when an electron attains the lowest energy level it is said to be in the ground state.

The electrons in an atom move from a lower energy level to a higher energy level by gaining the required energy and an electron moves from a higher energy level to lower energy level by losing energy.Bohr’s Model of an Atom

(b) the number of protons in an atom is called the atomic number.

A property closely related to an atom’s mass number is its atomic mass. The atomic mass of a single atom is simply its total mass and is typically expressed in atomic mass units or amu. By definition, an atom of carbon with six neutrons, carbon-12, has an atomic mass of 12 amu.