Questions

Hybridisation of Ni is e-  

Unpaired 3d8in  is 2 

So $$\begin{gathered} Ω = n(n+2)BM \\ =2x4 = 8 = 2.82BM \end{gathered}$$

Every year 5th September is celebrated as Teacher's Day in India, in the memory of Dr. Sarvepalli Radhakrishnan's birthday. He was the first vice-president and second president of India.

After he become the president of India, his students want to celebrate his birthday in grand but he refused and he adviced them to celebrate that day as teachers day. From then, 5th September is celebrated as Teacher's Day.

If as a business, you buy goods or services on credit from a supplier (accounts payable) then the supplier will supply the goods and business will incur a liability to the supplier for that amount, but no cash will change hands at that stage.

Some of those shop keepers allowed regular "trustworthy" customers to purchase items without having the full payment.

Hence, Buying on credit means that no actual money has changed hands.

When atoms react they do so in order to reach the lowest energy, which is the most stable. The electrons orbitals will overlap in the way that reduces the energy the most. Orbitals of similar energy will produce the greatest stabilisation.The answer you gave isn't the whole story, it depends what species is reacting with what. The effective nuclear charge on the atom will affect the energy of the valance electrons.

Hence, the reactivity of an atom arises from the existence of unpaired electrons in the valence shell.