Question

4. For an atom X, K, L and M shells are completely filled. How many electrons will be present in it? ​

Answer 1

Answer: 28 e-

Explanation:

In an orbit, there are 2n² electrons; where n = energy level index.

Therefore,

• in K shell, no. of e- = 2(1)² = 2
• L shell = 2(2)² = 8
• M = 2(3)² = 18

So, total e- = Z = 2 + 8 + 18 = 28 e-

More:

• The Bohr's model postulated that the electrons revolving in discrete orbits do not radiate energy. (This reason was a setback of Rutherford's model.)
• If an atom completes 2 atom in its K shell, (and total e- = 2) then it is said to follow the duplet rule and shows very less chemical activities.
• In a ionic bond, metal & non metal atoms donate and take electrons to form there chemical bond. After donating, metal atom becomes positive ion & non metal ion becomes negative ion thus, high electrostatic energy due to opposite charges.
• Covalent bond is formed when two ions share electrons. Ions become two types: • Lone pair • Bond pair.