Step 1: Use lewis structure guidelines to draw the lewis structure of BCl₃.

Step2: Apply VSEPR notation, A X E
A=Number of central atoms
X=Number of surrounding atoms
E= Number of lone pairs on central atom

For the above molecule VSEPR notation will be AX₂E₀

Step 3: Use VSEPR table to find the shape. AX₂ has linear shape. So the shape of BeF₂ molecule is linear.
Download a copy of VSEPR shapes table here

Bond angle in BeF₂

Bond angle of F-Be-F covalent bond in this molecule is 180º.The representation is shown below.

Image courtesy:wikipedia.com