A molecule has four bonded atoms around a central atom. The central atom does not have any lone pairs of electrons. An example is CCl4, here the central C atom has 4 valence electrons, and the C makes a covalent bond with each of the four Cl atoms. In a C-Cl covalent bond an electron pair is shared. After fur C-Cl bonds C is left with no valence electron, hence there are no lone pair of electrons on C. Each of the four C-Cl bonds is directed towards the four corners of a tetrahedron.
Tetrahedral. like methan ch4 it doesn t have lone pairs of electrons and the bonds are oriented with a 109* 28' angle and a tetrahedron has the angles of 109 degrees so almost the same.
