Structure and Hybridization:

How we can understand this? “Easy” by solving question based on it.

SP

Example 1^st: BeF_2 (sp - Hybridization₎

Write valence shell electronic configuration.

Be: 1s², 2s²

1 - Write orbital configuration of valence shell only.

2 - Excite electron of 2s orbital into vacant p - orbital.

3 - 2s + 2p, having equal energy, now they are Hybrid orbital :) 

4 - Hybrid orbital forms covalent bond with surrounded atoms such as F. 

Thus, sp - Hybridization in BeF₂

*What happen with 1s² orbital electrons?

It remains as non-bonded electrons i.e. lone pair. Thus in this example one lone pair is present in 1s orbital.

*What causes excitation of electron?

Presence of two F – atom causes this excitation.

*How F – atoms combine with this sp – Hybrid orbital?

C₂H_{2  (}sp - Hybridization₎

Reference: http://www.mhhe.com/physsci/chemistry/carey5e/Ch02/ch2-3-3.html

C₂H₄ (sp² Hybridization)

Reference: http://www.mhhe.com/physsci/chemistry/carey5e/Ch02/ch2-3-2.html