Question

1.Why Berillium is placed in fourth place and Boron is in fifth place in the periodic table?
2.Which is used to cut and grained glass?​

Answer 1

Explanation:

1. Electronic configuration of Be: 1s22s2

Electronic configuration of B: 1s22s22p1

Be has stable fully filled configuration, therefore more amount of energy is required to remove an electron from Be, whereas less amount of energy is required to remove an electron from valence p-orbital in B.  so Be is placed in fourth place.

1. Grinding wheels with aluminum oxide (corundum), silicon carbide, or ceramic grains are used to cut and grained glass.

Hope this helps you.