Which formula represents a polar molecule?
(1) h2 (3) co2
(2) h2o (4) ccl4

Molecules are said to be polar when there is a net dipole moment. 3D structures of molecules play an important role in this effect. Symmetrical molecules cancel out net dipile to 0.

H2, CO2 and CCl4 are all symmetrical, thus are non-polar.

H2O is structurally bent. It is polar.

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom

What? i don’t understand