The Lewis structure for BeH₂ molecule is as follows : H : Be : H
There is no lone pair at the central atom (Be) and there are two bond pairs. Hence, BeH₂ is of the type AB₂. It has a linear structure.

Dipole moments of each Be-H bond are equal and opposite in direction. Therefore, they nullify each other. Hence, BeH₂ has a net zero dipole moment.

(i) The shape of a molecule depends upon the no. of electron pairs around the central atom.
(ii) There is a repulsive force between the electron pairs, which tend to repel one another.
(iii) The electron pairs in space tend to occupy such positions that they are at maximum distance, so that the repulsive force will be minimum.
(iv) A multiple bond is treated as if it is a single bond and the remaining electron pairs which constitute the bond may be regarded as single super pair.

The outer shell electrons are shown as dots surrounding the symbol of the atom. These symbols are known as Lewis symbols or Lewis structures. The Lewis structure of
(i) H₂-H:H
(ii) 

(i) The combining atomic orbitals should have comparable energies. For example, ls orbital of one atom can combine with Is atomic orbital of another atom, 2s orbital can combine with 2s orbital and so on.
(ii) The combining atomic orbitals must have proper orientations so that they are able to overlap to a considerable extent.
(iii) The extent of overlapping should be large.