what hybrid orbitals would be expected for the central atom for the followings

a) BrF5
b) BeCl2
c) CH3Cl

To determine the hybrid orbitals for the central atom in a molecule, you need to consider the number of electron groups around it (including both bonding and lone pairs). The hybridization of an atom occurs when the electron groups are rearranged into new, equivalent hybrid orbitals.

a) BrF5:
The central atom in BrF5 is bromine (Br). Bromine has seven valence electrons, and each fluorine atom brings one additional valence electron. Adding these up, we have a total of 12 valence electrons (5 from bromine + 7 from fluorine).

In BrF5, there are five bonding groups (Br-F bonds) and one lone pair. Since there are six electron groups, sp3d2 hybridization would be expected for the central bromine atom. This means that bromine's 5s, 3p, and one 3d orbitals will combine to form six new hybrid orbitals called sp3d2.

b) BeCl2:
The central atom in BeCl2 is beryllium (Be). Beryllium has two valence electrons, and each chlorine atom brings seven additional valence electrons. Adding these up, we have a total of 16 valence electrons (2 from beryllium + 2 × 7 from chlorine).

In BeCl2, there are two bonding groups (Be-Cl bonds) and no lone pairs. Since there are two electron groups, sp hybridization would be expected for the central beryllium atom. This means that beryllium's 2s and one 2p orbitals will combine to form two new hybrid orbitals called sp.

c) CH3Cl:
The central atom in CH3Cl is carbon (C). Carbon has four valence electrons, and each hydrogen atom brings one additional valence electron. Adding these up, we have a total of 8 valence electrons (4 from carbon + 3 × 1 from hydrogen + 1 from chlorine).

In CH3Cl, there are four bonding groups (C-H bonds and C-Cl bond) and no lone pairs. Since there are four electron groups, sp3 hybridization would be expected for the central carbon atom. This means that carbon's 2s and two 2p orbitals will combine to form four new hybrid orbitals called sp3.

Remember that these are the expected hybridizations based on the number of electron groups. However, the actual hybridization may be influenced by other factors such as electronegativity and molecular geometry.